Fixes#60374
Some markdown-it extensions end up reprocessing the same tokens multiple times. This can result in our link normalized being re-invoked on a link, which causes it to fail
Fix to to make sure that `vscode-resource` is a recongized link so that we don't try re-normalizing in these cases
Fixes#58566
We only support local file links or a small set of normal schemes, like `http` and `mailto`. Use this to avoid calling `Uri.parse` with scheme-less paths such as `Uri.parse('/images/cat.gif')`
Matt Bierner