FileIconProvider: Use sound icon for flac file extension

Base/etc/FileIconProvider.ini

@@ -14,7 +14,7 @@ music=*.midi
 object=*.o,*.obj
 pdf=*.pdf
 python=*.py
-sound=*.wav
+sound=*.wav,*.flac
 spreadsheet=*.sheets
 text=*.txt
 truetype=*.ttf