QmlJS semantic highlighter: Use document instead of widget

Diagnostic ranges also move to document for this.

Change-Id: I82a9909abb57594cdd732448270849e6a2e3a4e0
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>

src/plugins/qmljseditor/qmljseditordocument_p.h

@@ -34,6 +34,7 @@
 #include <qmljstools/qmljssemanticinfo.h>
 
 #include <QObject>
+#include <QTextLayout>
 #include <QTimer>
 
 namespace QmlJSEditor {
@@ -64,6 +65,7 @@ public:
     int m_semanticInfoDocRevision; // document revision to which the semantic info is currently updated to
     SemanticInfoUpdater *m_semanticInfoUpdater;
     QmlJSTools::SemanticInfo m_semanticInfo;
+    QVector<QTextLayout::FormatRange> m_diagnosticRanges;
 };
 
 } // Internal