dash: Use pin instead of favorites

Use the term 'pin' for adding new items to the dash
Note that this is only a string change.

Fixes https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/4976

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2136>

js/ui/appMenu.js

@@ -160,8 +160,8 @@ var AppMenu = class AppMenu extends PopupMenu.PopupMenu {
 
         const { id } = this._app;
         this._toggleFavoriteItem.label.text = this._appFavorites.isFavorite(id)
-            ? _('Remove from Favorites')
-            : _('Add to Favorites');
+            ? _('Unpin')
+            : _('Pin to Dash');
     }
 
     _updateGpuItem() {