Add --audio-codec=raw option

Add support for raw (PCM S16 LE) audio codec (a raw decoder is included
in FFmpeg).

PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>

app/data/bash-completion/scrcpy

@@ -78,7 +78,7 @@ _scrcpy() {
             return
             ;;
         --audio-codec)
-            COMPREPLY=($(compgen -W 'opus aac' -- "$cur"))
+            COMPREPLY=($(compgen -W 'opus aac raw' -- "$cur"))
             return
             ;;
         --lock-video-orientation)