[workspace] workspace.supportMultiRootWorkspace is enabled by default

[svenefftinge]

What it does

Enables workspace.supportMultiRootWorkspace by default.

Fixes #6088

How to test

Start theia and see how multiroot workspaces are enabled.
E.g. Save workspace as ... menu item is enabled.

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[akosyakov]

@marcdumais-work @vince-fugnitto do you know when @elaihau is available next time? Maybe someone else can check whether all clients are respecting multi-root workspaces, and not simply fallback to the first root.

I know for sure that for LSP support of multi-roots #5901 is required.

[kpge]

I think the description should be changed also.

[vince-fugnitto]

@marcdumais-work @vince-fugnitto do you know when @elaihau is available next time? Maybe someone else can check whether all clients are respecting multi-root workspaces, and not simply fallback to the first root.

I know that @elaihau will be in the Montreal offices on Friday, but I'm not sure when else during the week he will be working remotely.

[svenefftinge]

I just assigned @elaihau because he was proposed. Happy to go with any review :-)
Will fix the description now.

[lmcbout]

Minor comments to adjust before merging
Works fine

[lmcbout]

This line should not be under the version v.0.3.11, but under the next release on top of the file (v0.10.1 or v0.11)

[lmcbout]

Looks good

[svenefftinge]

I know for sure that for LSP support of multi-roots #5901 is required.

@akosyakov could you clarify? I use multi-root workspace with a go mono repo. Because the Go language server (gopls) wants every module to be in a root. In that case LSP seems to work fine.

[akosyakov]

@svenefftinge It affects only if a language server supports multiple workspace roots, we were reporting only first. It also does not affect VS Code extensions, only native extensions.

[akosyakov]

I've reviewed all usages of roots and seems like all clients are capable to handle multiple roots.
Also tested a bit with single root and everything behaves well too.

[vince-fugnitto]

I'm wondering if there's actually a need for the preference. In the past the preference was used to turn off the feature since it was experimental. Now that the preference is enabled I'm wondering if we should simply remove it.

Multi-root workspace support would then only be enabled the moment a user adds a new root.