workspace-indicator: Don't mention "top bar" in prefs

The preferences will be shared with the window-list extension,
so avoid mentioning a specific placement.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell-extensions/-/merge_requests/344>

extensions/workspace-indicator/workspacePrefs.js

@@ -26,7 +26,7 @@ class GeneralGroup extends Adw.PreferencesGroup {
         super();
 
         const row = new Adw.SwitchRow({
-            title: _('Show Previews In Top Bar'),
+            title: _('Show Previews'),
         });
         this.add(row);