Bug 1529897 - fix typo

toolkit/modules/LightweightThemeConsumer.jsm

@@ -135,7 +135,7 @@ function LightweightThemeConsumer(aDocument) {
 
   // We're responsible for notifying LightweightThemeManager when the OS is in
   // dark mode so it can activate the dark theme. We don't want this on Linux
-  // as default theme picks up the right colors from dark GTK themes.
+  // as the default theme picks up the right colors from dark GTK themes.
   if (AppConstants.platform != "linux") {
     this._darkThemeMediaQuery = this._win.matchMedia("(-moz-system-dark-theme)");
     this._darkThemeMediaQuery.addListener(this.LightweightThemeManager);