localResourceRoots should include extension folder in addition to workspace folder

[octref]

Testing #44466

Feel this is a saner default.

[mjbvz]

Already covered by the vscode-extension-resource scheme. The vscode-extension-resource resources are always available regardless of the localResourceRoots setting

[octref]

vscode-extension-resource

Can we start a documentation for the Webview early? I'm happy to set up yet another preview server where the team can see early documentation and give feedback. It would be nice to see the API and the doc evolving together.

Now it seems impossible to figure out how to include external js/css files (the <base> thing we talked about and the CSP rules). I don't even know if @jrieken or @tsalinger were able to test including external js/css from extension folder.

[tsalinger]

@octref good point! I was trying to include external js but didn't succeed.
In the meantime, Matt gave me some feedback on it and I'll try again later today.

[tsalinger]

For the record: I didn't manage to include an external js file.
@mjbvz would be cool if you could add a minimal example on how to do it.