Support arbitrary formatter?

[mightyiam]

I ran across https://github.com/kamadorueda/alejandra. I tried it. I liked it. But rnix-lsp doesn't seem to support using arbitrary formatters. So... Would this be a reasonable feature to ask?

[Ma27]

Last time I looked I wasn't too fond of it, but that was a few weeks ago, so things might've changed.
Anyways, this is IMHO reasonable, but I don't have the capacity atm to implement that, so feel free to file a PR if you'd like to. I'll add a "help wanted"-label to make this explicit.

[marcelarie]

@mightyiam idk if you use nvim, but if you do, you can use null-ls for the formatting with alejandra.

I just opened the PR today, still needs to be merged 😁