SVN workspace support

[seanbone]

I'm working on Fortran projects under SVN (I know, right?). The fortls server works a charm, however, with Helix I run in to the issue of workspace root detection. Helix doesn't seem to treat .svn folders as workspace-root markers and so by default it uses my home directory (which in turn causes fortls to time out because it's too much stuff).

After a lot of tinkering and looking at verbose logs, I was able to get it to work as desired in one of two ways:

1. Adding an empty .helix or .git directory to the workspace root. I seem to recall reading about this in the documentation a while ago, but I can't seem to find it any more. Is there a docs page that states exactly how the workspace root is determined by Helix? It would be helpful for this sort of debugging.
2. Using the roots option in the Fortran language in languages.toml: roots = [".fortls.json", ".svn"]. Works, but is limited to the Fortran language.

Neither of these solutions is ideal. It requires extra configuration steps either per language or per repository. As far as I can tell, this is not configurable in a generic way at the moment. Personally, the real strength of Helix over, eg, nvim, is that it "just works" most of the time.

I propose adding .svn as a criterion for workspace root detection. I would also be willing to provide a MR if given some pointers as to where in the codebase this happens.

[kirawi]

What version of Helix are you using? Svn is already recognized as a default root.

[kirawi]

I took a look and I was confusing this with #10536.

[seanbone]

I'm using a build based on master from a few months ago (I don't have the exact commit hash at hand).