fix syntax error

config.js

         // amplitudeAPPKey: '<APP_KEY>'
 
         // Configuration for the rtcstats server:
-+       // By enabling rtcstats server every time a conference is joined the rtcstats
+        // By enabling rtcstats server every time a conference is joined the rtcstats
         // module connects to the provided rtcstatsEndpoint and sends statistics regarding
         // PeerConnection states along with getStats metrics polled at the specified
         // interval.