What is a Weblink?
A weblink is a document of type "reference". Its template is not used to display or format the link, rather the template in this case simply serves as a container for any Template Variables that you may wish to append to your WebLink. The WebLink simply serves as a link that will be part of a generated menu.
The content of the weblink is just an URL; the parser doesn't even parse it, MODX simply redirects to the URL. As soon as it sees that it is a "reference", it just uses the content as the argument for sendRedirect($url).
You can use an external URL for the content, or you can use a Resource ID to link to a Resource in your MODX Resource tree.
Or, you could do it the other way around, have the Contact Us Resource in your unpublished "utility pages" folder, and put the Weblink to it in your top-level so it will show in the main menu.
Originally a menu snippet would make the link to the Weblink itself, just as to any other MODX resource, thus causing the page to be loaded by the parser, triggering the redirect.