Add missing overrides

Fix-up of b0bee4b947 which introduced
override for some of the overridden methods.

Change-Id: If7c47a402a9fbce53bae37702afec60de0960552
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/coreplugin/locator/spotlightlocatorfilter.mm

@@ -50,10 +50,10 @@ class SpotlightIterator : public BaseFileFilter::Iterator
 {
 public:
     SpotlightIterator(const QString &expression);
-    ~SpotlightIterator();
+    ~SpotlightIterator() override;
 
-    void toFront();
-    bool hasNext() const;
+    void toFront() override;
+    bool hasNext() const override;
     Utils::FilePath next() override;
     Utils::FilePath filePath() const override;