Update TROUBLESHOOTING.md

TROUBLESHOOTING.md

@@ -257,7 +257,7 @@ Is triple the default for the ALSA backend and effectively solves the above issu
 
 ### AAC Decoder Issues (AirPlay 2 only)
 
-To play AirPlay 2 Buffered Audio streams, Shairport Sync needs an AAC decoder capable of decoding Floating Planar -- `fltp` -- AAC material. Unfortunately, not all systems have such a decoder. The idea here is to use the `ffmpeg` app to list AAC decoders and to check that the default AAC decoder has `fplp` capability. Here is an example of where the AAC decoder _can_ decode `fltp` material. The system is a Raspberry Pi running 64-bit Raspberry Pi OS Lite 11 (Bullseye):
+To play AirPlay 2 Buffered Audio streams, Shairport Sync needs an AAC decoder capable of decoding Floating Planar -- `fltp` -- AAC material. Unfortunately, not all systems have such a decoder. The idea here is to use the [`ffmpeg`](https://www.ffmpeg.org) app, which may already be installed in your system, to list AAC decoders and to check that the default AAC decoder has `fplp` capability. Here is an example of where the AAC decoder _can_ decode `fltp` material. The system is a Raspberry Pi running 64-bit Raspberry Pi OS Lite 11 (Bullseye):
 ```
 $ ffmpeg -decoders | grep -i aac