TextEditor: Simplify testing of code assistant

Change-Id: I6f16dd775a7c5d8eaa4944d6050bf979be83a303
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/texteditor/basetexteditor.h

@@ -332,8 +332,12 @@ public slots:
     void openLinkUnderCursor();
     void openLinkUnderCursorInNextSplit();
 
+    /// Abort code assistant if it is running.
+    void abortAssist();
+
 signals:
     void changed();
+    void assistFinished();
 
     // ITextEditor
     void contentsChanged();