QmlDesigner: Adding support for font weight

We have to tell the rewriter that an enum scope called "Font"
does exist.

Change-Id: Ib77a099d94ec84b99e54e3c9151249df53eb53fa
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

share/qtcreator/qmldesigner/propertyEditorQmlSources/HelperWidgets/FontSection.qml

@@ -142,6 +142,18 @@ Section {
 
         }
 
+        Label {
+            text: qsTr("Font weight")
+            toolTip: qsTr("Sets the font's weight.")
+        }
+
+        ComboBox {
+            Layout.fillWidth: true
+            backendValue: backendValues.font_weight
+            model:  ["Normal", "Light", "ExtraLight", "Thin", "Medium", "DemiBold", "Bold", "ExtraBold", "Black"]
+            scope: "Font"
+        }
+
         Label {
             visible: showStyle
             text: qsTr("Style")

src/plugins/qmldesigner/designercore/model/texttomodelmerger.cpp

@@ -90,7 +90,7 @@ static inline QStringList globalQtEnums()
 static inline QStringList knownEnumScopes()
 {
     static const QStringList list = {
-        "TextInput", "TextEdit", "Material", "Universal"
+        "TextInput", "TextEdit", "Material", "Universal", "Font"
     };
     return list;
 }