UiCodeModelSupport: Notify if content changes

Needed for ClangCodeModel.

If the content changes, we want to send it immediately to the
codemodelbackend process.

Change-Id: Iedf16930b494ccb5e91f1bc435db026067d98613
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>
Reviewed-by: Daniel Teske <daniel.teske@theqtcompany.com>

src/plugins/cpptools/abstracteditorsupport.h

@@ -51,6 +51,7 @@ public:
     virtual QString fileName() const = 0;
 
     void updateDocument();
+    void notifyAboutUpdatedContents() const;
     unsigned revision() const { return m_revision; }
 
     static QString licenseTemplate(const QString &file = QString(), const QString &className = QString());