TextEditor: Add a helper function to set up code assistance

This is needed for further refactoring in the cpp and qmljs editors.

Change-Id: Ic25525e5f468e915226e9daa8d118ff76a749e9f
Reviewed-by: Christian Stenger <christian.stenger@digia.com>

src/plugins/texteditor/basetexteditor.h

@@ -203,6 +203,8 @@ public:
     // FIXME: Only used to delay initialization from CppEditor.
     // There should be something simpler.
     void setCompletionAssistProvider(const std::function<CompletionAssistProvider *()> &provider);
+    // FIXME: Remove.
+    void configureCodeAssistant();
 
 signals:
     void markRequested(TextEditor::BaseTextEditor *editor, int line, TextEditor::BaseTextEditor::MarkRequestKind kind);