Use Command key instead of Control as modifier on macOS

This provides an experience closer to the original classic Mac version.

This is supported by the earlier changes to gracefully quit the game.

PortabilityLayer/MenuManager.cpp

@@ -1405,14 +1405,22 @@ namespace PortabilityLayer
 
 	size_t MenuManagerImpl::FormatHintText(uint8_t *buffer, uint8_t key)
 	{
+#ifdef __MACOS__
+		buffer[0] = 'C';
+		buffer[1] = 'm';
+		buffer[2] = 'd';
+		buffer[3] = '+';
+		buffer[4] = key;
+		return 5;
+#else
 		buffer[0] = 'C';
 		buffer[1] = 't';
 		buffer[2] = 'r';
 		buffer[3] = 'l';
 		buffer[4] = '+';
 		buffer[5] = key;
-
 		return 6;
+#endif
 	}
 
 	MenuManagerImpl *MenuManagerImpl::GetInstance()