Fix some warnings about unused things

Change-Id: I42bb514dfe1d6745b1469b508a4cfa576e17c31b
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/plugins/fakevim/fakevimplugin.cpp

@@ -812,7 +812,7 @@ public:
         setId(SETTINGS_USER_CMDS_ID);
         setDisplayName(Tr::tr("User Command Mapping"));
         setCategory(SETTINGS_CATEGORY);
-        setWidgetCreator([this] { return new FakeVimUserCommandsPageWidget; });
+        setWidgetCreator([] { return new FakeVimUserCommandsPageWidget; });
     }
 };