Allow Custom Links in the Contextual Menu to Use $path in the Base of the URL

[brycewc]

Right now, you can add $path to a custom link in the contextual menu to grab the path of the current page, but you can only use that in the query param of the URL you are producing. It would be great to have a direct link to the file of the current page in GitHub, but this requires the $path variable to be used in the base of the URL, like https://github.com/user/repo/blob/main/$path