Rename --no-display to --no-mirror

The option impacts both video and audio playback, so "no display" is not
an appropriate name.

PR #3978 <https://github.com/Genymobile/scrcpy/pull/3978>

doc/recording.md

@@ -18,7 +18,7 @@ _It is currently not possible to record only the audio._
 To disable mirroring while recording:
 
 ```bash
-scrcpy --no-display --record=file.mp4
+scrcpy --no-mirror --record=file.mp4
 scrcpy -Nr file.mkv
 # interrupt recording with Ctrl+C
 ```