[RN] Fix documentation

android/README.md

 Called when a joining a conference was unsuccessful or when there was an error
 while in a conference.
 
-The `data` HashMap contains an "error" key describing the error and a "url"
-key with the conference URL.
+The `data` `Map` contains an "error" key describing the error and a "url" key
+with the conference URL.
 
 #### onConferenceJoined
 
 Called when a conference was joined.
 
-The `data` HashMap contains a "url" key with the conference URL.
+The `data` `Map` contains a "url" key with the conference URL.
 
 #### onConferenceLeft
 
 Called when a conference was left.
 
-The `data` HashMap contains a "url" key with the conference URL.
+The `data` `Map` contains a "url" key with the conference URL.
 
 #### onConferenceWillJoin
 
 Called before a conference is joined.
 
-The `data` HashMap contains a "url" key with the conference URL.
+The `data` `Map` contains a "url" key with the conference URL.
 
 #### onConferenceWillLeave
 
 Called before a conference is left.
 
-The `data` HashMap contains a "url" key with the conference URL.
+The `data` `Map` contains a "url" key with the conference URL.
 
 #### onLoadConfigError
 
 Called when loading the main configuration fails.
 
-The `data` HashMap contains a "error" key with the error.
+The `data` `Map` contains an "error" key with the error.

android/sdk/src/main/java/org/jitsi/meet/sdk/JitsiMeetViewListener.java

     /**
      * Called when loading the main configuration fails.
      *
-     * @param data - Map with a "error" key with the error.
+     * @param data - Map with an "error" key with the error.
      */
     void onLoadConfigError(Map<String, Object> data);
 }

ios/README.md

 
 Called when loading the main configuration fails.
 
-The `data` dictionary contains a "error" key with the error.
+The `data` dictionary contains an "error" key with the error.

ios/sdk/src/JitsiMeetViewDelegate.h

 /**
  * Called when loading the main configuration file fails.
  *
- * The {@code data} dictionary contains a {@code error} key with the error.
+ * The {@code data} dictionary contains an {@code error} key with the error.
  */
 - (void) loadConfigError:(NSDictionary *)data;