TextEditor: Move comment definitions back to *Widget

Only used there, and avoids back-links to editors.

Change-Id: I81206057ce89d42aef7febb840cf9e44b869df0e
Reviewed-by: Christian Stenger <christian.stenger@digia.com>

src/plugins/cppeditor/cppeditorplugin.cpp

@@ -91,6 +91,7 @@ public:
         setEditorWidgetCreator([]() { return new CppEditorWidget; });
         setEditorCreator([]() { return new CppEditor; });
         setAutoCompleterCreator([]() { return new CppAutoCompleter; });
+        setCommentStyle(Utils::CommentDefinition::CppStyle);
 
         setEditorActionHandlers(Constants::C_CPPEDITOR,
                                 TextEditorActionHandler::Format