feat(gh_actions_ls): use root_dir to decide whether to attach

[chrisgrieser]

cc @disrupted

This saves the user the extra setup work of copypasting the vim.filetype.add snippet, making this language server work out of the box.

Follow-up to #3551, on this suggestion: https://github.com/neovim/nvim-lspconfig/pull/3551/files#r1912833011

[disrupted]

I agree that this is probably a sensible default and less manual maintenance for users. Although personally, I am not a fan of the runtime check and will likely continue using the special filetype as it keeps things tidier.
We should also decide on a common strategy. gitlab_ci_ls is a very similar candidate

[justinmk]

We should also decide on a common strategy. gitlab_ci_ls is a very similar candidate

Agreed. I have never seen a .github file on any project I'm familiar with, so the runtime check is probably the right approach.

[disrupted]

I have never seen a .github file on any project I'm familiar with, so the runtime check is probably the right approach.

d'oh. That was meant for the .github folder that contains workflows etc. I believe the root pattern function works on folders as well as files, does it not?

[justinmk]

That was meant for the .github folder that contains workflows etc. I believe the root pattern function works on folders as well as files, does it not?

Oh sorry I saw yaml.github in #3551 (comment) and didn't look closely enough. I see now that it's only defining a filetype with that name.

In any case, avoiding the need for users to manually call vim.filetype.add() in their configs, is worthwhile. However it may require the single_file_support=false trick as mentioned in this PR.