Bug 1794577 - Enable aspect-ratio locking on KDE too. r=stransky

Seems to work nicely.

Differential Revision: https://phabricator.services.mozilla.com/D171077

widget/gtk/nsWindow.cpp

@@ -8466,9 +8466,8 @@ static nsresult initialize_prefs(void) {
   if (Preferences::HasUserValue("widget.use-aspect-ratio")) {
     gUseAspectRatio = Preferences::GetBool("widget.use-aspect-ratio", true);
   } else {
-    gUseAspectRatio = IsGnomeDesktopEnvironment();
+    gUseAspectRatio = IsGnomeDesktopEnvironment() || IsKdeDesktopEnvironment();
   }
-
   return NS_OK;
 }