SourceLinkMap does not provide relative file paths.

For tools that actually leverage SourceLink, it is good to have (what I call) the "repo relative file path". I believe this is equivalent to the portion of the document file path that is after the source root. In practice, this is whatever replaces the "*" in the json source link map.

VS Debugger uses this internally. It allows for caching the retrieved source link files in a directory structure that resembles the original repo. It would be helpful if SourceLinkMap could provide this as well.