fix(docs): correct the grammar in token docs

doc/tokens.md

 JWT token authentication Prosody plugin
 ==================
 
-This plugin implements Prosody authentication provider that verifies client connection based on JWT token described in [RFC7519].
-It allows to use any external form of authentication with lib-jitsi-meet. Once your user authenticates you need to
-generate the JWT token as described in the RFC and pass it to your client app. Once it connects with valid token is considered authenticated by jitsi-meet system.
+This plugin implements a Prosody authentication provider that verifies a client connection based on a JWT token described in [RFC7519].
+It allows use of an external form of authentication with lib-jitsi-meet. Once your user authenticates you need to
+generate the JWT token as described in the RFC and pass it to your client app. Once it connects with a valid token it is considered authenticated by the jitsi-meet system.
 
-During configuration you will need to provide the *application ID* that identifies the client and a *secret* shared by both server and JWT token generator. Like described in the RFC, secret is used to compute HMAC hash value which allows to authenticate generated token. There are many existing libraries which can be used to implement token generator. More info can be found here: [http://jwt.io/#libraries-io]
+During configuration you will need to provide the *application ID* that identifies the client and a *secret* shared by both server and JWT token generator. Like described in the RFC, the secret is used to compute a HMAC hash value which allows authentication of the generated token. There are many existing libraries which can be used to implement token generation. More info can be found here: [http://jwt.io/#libraries-io]
 
-JWT token authentication currently works only with BOSH connections.
+JWT token authentication only currently works with BOSH connections.
 
 [RFC7519]: https://tools.ietf.org/html/rfc7519
 [http://jwt.io/#libraries-io]: http://jwt.io/#libraries-io
 
 ### Token structure
 
-The following JWT claims are used in authentication token:
-- 'iss' specifies *application ID* which identifies the client app connecting to the server. It should be negotiated with the service provider before generating the token.
-- 'room' contains the name of the room for which the token has been allocated. This is *NOT* full MUC room address. Example assuming that we have full MUC 'conference1@muc.server.net' then 'conference1' should be used here.  Alternately, a '*' may be provided, allowing access to all rooms within the domain.
+The following JWT claims are used in the authentication token:
+- 'iss' specifies the *application ID* which identifies the client app connecting to the server. It should be negotiated with the service provider before generating the token.
+- 'room' contains the name of the room for which the token has been allocated. This is *NOT* the full MUC room address. An example assuming that we have full MUC 'conference1@muc.server.net' would be that 'conference1' should be used here.  Alternately, a '*' may be provided, allowing access to all rooms within the domain.
 - 'exp' token expiration timestamp as defined in the RFC
 - 'sub' contains EITHER the lowercase name of the tenant (for a conference like TENANT1/ROOM with would be 'tenant1') OR the lowercase name of the domain used when authenticating with this token (for a conference like /ROOM). By default assuming that we have full MUC 'conference1@muc.server.net' then 'server.net' should be used here.  Alternately, a '*' may be provided, allowing access to rooms in all tenants within the domain or all domains within the server.
 - 'aud' application identifier. This value indicates what service is consuming the token.  It should be negotiated with the service provider before generating the token.
 
-Secret is used to compute HMAC hash value and verify the token for HS256 tokens.  
+The secret is used to compute the HMAC hash value and verify the token for HS256 tokens.  
 
-Alternately the token may be signed by a private key and authorized via public keyserver using RS256 tokens.  In this mode, the 'kid' header of the JWT must be set to the name of the public key.  The backend server must be configured to fetch and confirm keys from a pre-configured public keyserver.
+Alternately the token may be signed by a private key and authorized via a public keyserver using RS256 tokens.  In this mode, the 'kid' header of the JWT must be set to the name of the public key.  The backend server must be configured to fetch and confirm keys from a pre-configured public keyserver.
 
 ### Token Identifiers
 
   - 'email' is the email of the user
   - 'avatar' is the URL of the avatar for the user
 > Note: As the moment all fields in 'user' need to be a valid string, numeric types or `null` will generate an exception.
-- 'callee' is an optional object containing display information when launching a 1-1 video call with a single other participant.  It used to display an overlay to the first user, before the second user joins.
+- 'callee' is an optional object containing display information when launching a 1-1 video call with a single other participant. It is used to display an overlay to the first user, before the second user joins.
   - 'id' is a user identifier string.  Intended for use in reporting/analytics
   - 'name' is the display name of the 'callee' user
   - 'avatar' is the URL of the avatar of the 'callee'
     modules_enabled = { "presence_identity" }
 ```
 
-The data is now available as the identity in the JitsiParticipant class. You can access them by e.g. listening to the `USER_JOINED` event.
+The data is now available in the identity in the JitsiParticipant class. You can access them by e.g. listening to the `USER_JOINED` event.
 
 NOTE: The values in the token shall always be valid values. If you define e.g. the avatar as `null` it will throw an error.
 
 ### Token verification
 
 JWT token is currently checked in 2 places:
-- when user connects to Prosody through BOSH. Token value is passed as 'token' query paramater of BOSH URL. User uses XMPP anonymous authentication method.
-- when MUC room is being created/joined Prosody compares 'room' claim with the actual name of the room. In addition, the 'sub' claim is compare to either the tenant (for TENANT/ROOM URLs) or the base domain (for /ROOM URLs).  This prevents stolen token being abused by unathorized users to allocate new conference rooms in the system. Admin users are not required to provide valid token which is used by Jicofo for example.
+- when a user connects to Prosody through BOSH. The token value is passed as the 'token' query paramater of the BOSH URL. User uses XMPP anonymous authentication method.
+- when a MUC room is being created/joined Prosody compares the 'room' claim with the actual name of the room. In addition, the 'sub' claim is compare to either the tenant (for TENANT/ROOM URLs) or the base domain (for /ROOM URLs).  This prevents a stolen token being abused by unathorized users to allocate new conference rooms in the system. Admin users are not required to provide a valid token which is used for example by Jicofo.
 
 ### Lib-jitsi-meet options
 
-When JWT authentication is used with *lib-jitsi-meet* the token is passed to *JitsiConference* constructor:
+When JWT authentication is used with *lib-jitsi-meet* the token is passed to the *JitsiConference* constructor:
 
 ```
 var token = {token is provided by your application possibly after some authentication}
 
 ### Jitsi-meet options
 
-In order to start jitsi-meet conference with token you need to specify the token as URL param:
+In order to start a jitsi-meet conference with a token you need to specify the token as an URL param:
 ```
 https://example.com/angrywhalesgrowhigh?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ
 ```
-At current level of integration every user that joins the conference has to provide the token and not just the one who
-creates the room. It should be possible to change that by using second anonymous domain, but that hasn't been tested
+At the current level of integration every user that joins the conference has to provide the token and not just the one who
+creates the room. It should be possible to change that by using a second anonymous domain, but that hasn't been tested
 yet.
 
 
 
-### Installing token plugin
+### Installing the token plugin
 
-Token authentication can be integrated automatically using Debian package install. Once you have jitsi-meet installed
+Token authentication can be integrated automatically using a Debian package install. Once you have jitsi-meet installed
 just install 'jitsi-meet-tokens' on top of it. In order to have it configured automatically at least version 779 of
-jitsi-meet is required which comes with special Prosody config template.
+jitsi-meet is required which comes with a special Prosody config template.
 
 ```
 apt-get install jitsi-meet-tokens
 Include "conf.d/*.cfg.lua"
 ```
 
-Also check if client to server encryption is not enforced. Otherwise token authentication won't work:
+Also check if client to server encryption is enforced. If not then token authentication won't work:
 ```
 c2s_require_encryption=false
 ```
 
 Modify your Prosody config with these three steps:
 
-\1. Adjust *plugin_paths* to contain the path pointing to jitsi meet Prosody plugins location. That's where plugins are copied on *jitsi-meet-token* package install. This should be included in global config section(possibly at the beginning of your host config file).
+\1. Adjust *plugin_paths* to contain the path pointing to the jitsi meet Prosody plugins location. That's where plugins are copied on *jitsi-meet-token* package installation. This should be included in the global config section (possibly at the beginning of your host config file).
 
 ```lua
 plugin_paths = { "/usr/share/jitsi-meet/prosody-plugins/" }
 ```
 
-Also optionally set the global settings for key authorization.  Both these options default to the '*' parameter which means accept any issuer or audience string in incoming tokens
+Also, optionally set the global settings for key authorization.  Both these options default to the '*' parameter which means accept any issuer or audience string in incoming tokens
 ```lua
 asap_accepted_issuers = { "jitsi", "some-other-issuer" }
 asap_accepted_audiences = { "jitsi", "some-other-audience" }
 ```
 
-\2. Under you domain config change authentication to "token" and provide application ID, secret and optionally token lifetime:
+\2. Under your domain config change authentication to "token" and provide the application ID, secret and optionally the token lifetime:
 
 ```lua
 VirtualHost "jitmeet.example.com"
 ```
 
 
-\3. Enable room name token verification plugin in your MUC component config section:
+\3. Enable the room name token verification plugin in your MUC component config section:
 
 ```lua
 Component "conference.jitmeet.example.com" "muc"