Git: Allow clicking references in VcsOutputWindow

Fixes: QTCREATORBUG-16477
Change-Id: If1f36bec0826a3116e5261a270cd63a1536e13f5
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/vcsbase/vcsoutputwindow.h

@@ -76,6 +76,9 @@ public:
         Message, // A blue message text (e.g. "command has finished successfully")
     };
 
+signals:
+    void referenceClicked(const QString &reference);
+
 public slots:
     static void setRepository(const QString &);
     static void clearRepository();