Update DESIGN

DESIGN.md

@@ -65,7 +65,7 @@ On VS Code, typed characters in text editors are treated differently than other
 
 As far as I know, an extension is allowed to override the `type` built-in command using `vscode.commands.registerCommand` API. Actually, the VSCodeVim extension seems to do that to customize the behavior for typed characters.
 
-It was not clear whether overriding the `type` command to capture typed characters is a good way for this extension. Especially if you use this extension combined with another extension that is overriding the `type` command too, there would be a conflict, and likely they will not work correctly.
+It was not clear whether overriding the `type` command to capture typed characters is a good way for this extension. Especially if you use this extension combined with another extension that is overriding the `type` command too, there would be a conflict, and likely they will not work correctly. See [vscode#13441](https://github.com/Microsoft/vscode/issues/13441).
 
 So this extension took another way to capture typed characters. That is to listen to the events on changes on the text document. Basically this is possible through the `vscode.workspace.onDidChangeTextDocument` event.