Fixes#155552
For lists, the outer ul/ol always has the same source line as the first element in the list. We should prefer using the first element in the list when highlighting the active line
This also fixes a bug where scroll sync would stop working if you added lines to the doc. This was caused by `lineCount` getting out of sync as the document is being updated. I've removed this state and made the reveal logic more robust instead
Splits the preview part of the markdown preview from the dynamic preview management part of things. Static preview swap to preview the active markdown file and don't scroll sync with any other markdown files
Fixes#72155
Adds a constant to the api that tracks the root path for resources inside of webviews. This is required because we will not be able to use `vscode-resource:` uris on the web. Our current approach is to rewrite the html we are given but there are almost certainly going to be cases where we don't get this quite right.
Adopts the new api for the markdown preview
