Open local external docs through remote VS Code authorities

[M-Nabeegh]

Fixes #23057

What changed

Translate local documentation links returned by rust-analyzer for remote editors into host-openable links. WSL authorities use the host's file://///wsl.localhost/<distro>/... UNC form so local HTML docs open in the default browser; other remote authorities use vscode-remote:// links with a :1:1 file position so VS Code opens the document instead of treating it as a folder. Local, web, and already-remote links keep their existing behavior.

Why

The VS Code extension host can receive a local documentation path from the remote language server, but opening that file:// URI targets the wrong side of the connection. A remote protocol URL without a file position is also interpreted as a folder by VS Code.

Validation

• npm run format:check
• npm run lint
• npm run typecheck
• npm test (VS Code 1.93.0 with a short user-data directory)
• Added unit coverage for WSL UNC conversion, SSH authorities, encoded paths, query strings, fragments, file positions, and unchanged URI forms.

[ChayimFriedman2]

Did you use AI for this? Please note that our AI policy:

• Requires disclosure.
• Requires understanding the code to the level you could write it yourself.
• Does not allow using AI to write GitHub comments and PR descriptions.

[M-Nabeegh]

Hi! I’m a 4t year CS student, and my professor asked us to make an open-source contribution sooo I’m still learning the contribution process. I did use AI assistance while working on this PR, and I apologize for not disclosing that earlier. I understand the code and the changes I submitted, and I’ll make sure to follow the project’s AI policy properly going forward. Thank you for pointing this out and for your understanding.