loplugin:unnecessaryoverride look for more patterns

like
   bool Foo::bar() {
       b = Super::bar();
       return b;
   }

Change-Id: I5e4c8005a3da7d7487c9039c35dcbb1d17e65bd7
Reviewed-on: https://gerrit.libreoffice.org/68418
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>

compilerplugins/clang/test/unnecessaryoverride.cxx

@@ -177,4 +177,17 @@ struct Derived5 : public Base5_1, public Base5_2
     void f1() { Base5_1::f1(); } // no warning expected
 };
 
+struct Base6_1
+{
+    bool f1();
+};
+struct Derived6 : public Base6_1
+{
+    bool
+    f1() // expected-error {{public function just calls public parent [loplugin:unnecessaryoverride]}}
+    {
+        bool ret = Base6_1::f1();
+        return ret;
+    }
+};
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */