AK+LibGUI: Pass predicate to *_matching() methods by const reference

Author: https://github.com/obyknovenius
Commit: a0a4d169f4
Pull-request: https://github.com/SerenityOS/serenity/pull/13641
Reviewed-by: https://github.com/ldm5180 ✅

Userland/Libraries/LibGUI/ModelSelection.h

@@ -76,7 +76,7 @@ public:
         return *m_indices.begin();
     }
 
-    void remove_all_matching(Function<bool(ModelIndex const&)> filter);
+    void remove_all_matching(Function<bool(ModelIndex const&)> const& filter);
 
     template<typename Function>
     void change_from_model(Badge<SortingProxyModel>, Function f)