Qmljs: small QHash improvements

Change-Id: I79a5504c8471b66540aac8047fbcf760ceb6b10f
Reviewed-by: Marco Benelli <marco.benelli@qt.io>

src/plugins/qmljstools/qmljsmodelmanager.h

@@ -60,6 +60,7 @@ private slots:
     void updateDefaultProjectInfo();
 private:
     void loadDefaultQmlTypeDescriptions();
+    QHash<QString, QmlJS::Dialect> initLanguageForSuffix() const;
 };
 
 } // namespace Internal