CppEditor: Avoid connecting multiple times to lambda

cppincludehierarchy.cpp:516:8: warning: UniqueConnection is not
supported with non-member functions

Change-Id: I9d4e743aa2fb4c05df85f566ccea7da98587d31b
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/cppeditor/cppincludehierarchy.cpp

@@ -509,9 +509,9 @@ void CppIncludeHierarchyWidget::syncFromEditorManager()
 
     // Use cppDocumentUpdated to catch parsing finished and later file updates.
     // The timer limits the amount of hierarchy updates.
-    connect(document, &CppEditorDocument::cppDocumentUpdated, this, [this]() {
-        m_timer->start();
-    }, Qt::UniqueConnection);
+    connect(document, &CppEditorDocument::cppDocumentUpdated,
+            m_timer, QOverload<>::of(&QTimer::start),
+            Qt::UniqueConnection);
 }
 
 // CppIncludeHierarchyFactory