fix (Qt) issues found by clang's clazy tool:

+ -Wclazy-incorrect-emit
+ -Wclazy-strict-iterators
+ -Wclazy-overloaded-signal
+ -Wclazy-qstring-arg
+ -Wclazy-unused-non-trivial-variable
+ -Wclazy-container-anti-pattern
+ -Wclazy-range-loop-reference
+ -Wclazy-const-signal-or-slot
+ -Wclazy-detaching-temporary
+ -Wclazy-qfileinfo-exists

src/Gui/ViewProviderGeoFeatureGroupExtension.h

@@ -52,11 +52,11 @@ public:
 
     /// Show the object in the view: suppresses behavior of DocumentObjectGroup
     virtual void extensionShow(void) override {
-        ViewProviderExtension::extensionShow();
+        ViewProviderExtension::extensionShow(); // clazy:exclude=skipped-base-method
     }
     /// Hide the object in the view: suppresses behavior of DocumentObjectGroup
     virtual void extensionHide(void) override {
-        ViewProviderExtension::extensionHide();
+        ViewProviderExtension::extensionHide(); // clazy:exclude=skipped-base-method
     }
 
     virtual void extensionUpdateData(const App::Property*) override;