Fix incorrect UI for Automation Track on Mac OS X

src/tracks/SampleTrack.cpp

@@ -266,7 +266,12 @@ void SampleTCOView::contextMenuEvent( QContextMenuEvent * _cme )
 					tr( "Paste" ), m_tco, SLOT( paste() ) );
 	contextMenu.addSeparator();
 	contextMenu.addAction( embed::getIconPixmap( "muted" ),
-				tr( "Mute/unmute (<Ctrl> + middle click)" ),
+				tr( "Mute/unmute (<%1> + middle click)" ).arg(
+					#ifdef LMMS_BUILD_APPLE
+					"⌘"),
+					#else
+					"Ctrl"),
+					#endif
 						m_tco, SLOT( toggleMute() ) );
 	contextMenu.addAction( embed::getIconPixmap( "record" ),
 				tr( "Set/clear record" ),