docs: add Android 11 support

[robingenz]

The following information should be added to the documentation:

Apps targeting Android 11 that use text-to-speech should declare TextToSpeech.Engine.INTENT_ACTION_TTS_SERVICE in the queries elements of their manifest: 

 <queries>
   ...
  <intent>
      <action android:name="android.intent.action.TTS_SERVICE" />
  </intent>
 </queries>

Source: https://developer.android.com/reference/android/speech/tts/TextToSpeech