cppeditor: s/Q_DECL_OVERRIDE/override/g

Change-Id: Ie0b75ea64ec3927732b484983311990c8ca0d057
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/plugins/cppeditor/cppquickfixes.cpp

@@ -4017,7 +4017,7 @@ public:
                 : QuickFixFactory::tr("Convert to Pointer"));
     }
 
-    void perform() Q_DECL_OVERRIDE
+    void perform() override
     {
         ChangeSet changes;