GUI: Update Roland GS description in MT-32 tab

Clarified the Roland GS settings. The current description is only partially accurate and confusing at best.

gui/options.cpp

@@ -887,7 +887,7 @@ void OptionsDialog::addMT32Controls(GuiObject *boss, const Common::String &prefi
 		_mt32Checkbox = new CheckboxWidget(boss, prefix + "mcMt32Checkbox", _c("True Roland MT-32 (no GM emulation)", "lowres"), _("Check if you want to use your real hardware Roland-compatible sound device connected to your computer"));
 
 	// GS Extensions setting
-	_enableGSCheckbox = new CheckboxWidget(boss, prefix + "mcGSCheckbox", _("Roland GS Mode (disable GM mapping)"), _("Turns off General MIDI mapping for games with Roland MT-32 soundtrack"));
+	_enableGSCheckbox = new CheckboxWidget(boss, prefix + "mcGSCheckbox", _("Roland GS Device (enable MT-32 mappings)"), _("Check if you want to enable patch mappings to emulate an MT-32 on a Roland GS device"));
 
 	const MusicPlugin::List p = MusicMan.getPlugins();
 	// Make sure the null device is the first one in the list to avoid undesired