Add TODO: into XAML so that is shows on my task list in visual studio
Sorry to be the one with the bad news, but it is not possible yet. A ticket has already been created in Microsoft Connect for that feature to be implemented. For now, you'll have to rely on your search.
-D
In Visual Studio 2015 and 2017 at least, one can create a "Shortcut" (VS Docs), which is a Bookmark in code that is tracked as Task by Task list. Shortcuts can be created in XAML code and are tracked too.
I just create a one line XAML comment and put Shortcut on that line (Ctrl+K, Ctrl+H)
<!-- TODO: Color buttons: Delete - red, Edit - yellow, New - green -->
This function may exist in earlier VS versions, but I can't verify.
(Yes, I know this is an old question, but it was a first result in Google for this, so I'm adding this breadcrumb for others that may end up here.)