Update TTS.md

Add information about running Edge TTS in plugin mode,

extensions/TTS.md

@@ -15,7 +15,7 @@ Used to select which TTS service you want to use.
 - **ElevenLabs** - paid subscription required, highest quality voices available at present.
 - **Silero** - free, runs on your PC, quality can vary widely
 - **System** - uses your OS TTS engine, if one exists. Quality can vary widely depending on the OS.
-- **Edge** - free, runs via Azure, generally quite fast, and voices feel natural but dry and emotionless. Like listening to the evening news or a radio announcer.
+- **Edge** - free, runs via Azure, generally quite fast, and voices feel natural but dry and emotionless. Like listening to the evening news or a radio announcer. When running with "Plugin" selected as the provider, you also need to install [this server plugin](https://github.com/SillyTavern/SillyTavern-EdgeTTS-Plugin), otherwise the TTS won't work.
 - **Coqui-TTS** - free, No API Implementation at this time. High-performance Text2Speech models (Tacotron, Tacotron2, Glow-TTS, SpeedySpeech) as well as Bark.
 - **Novel** - requires a paid NovelAI subscription, generated by NovelAI's TTS engine
 - **RVC** - free, voice cloning