plugins/lsp: add templ language server

[rsHalford]

Adds lsp support for templ, the HTML templating language for Go.

[GaetanLepage]

LGTM ! Thanks for your contribution :)

[psyos10]

Hey, new to nixos, may be my problem. I have been getting nixos-rebuild issues that point to this addition in nixvim, error: attribute 'templ' missing at plugins/lsp/helpers.nix:6:15 , my config worked fine before this.

[traxys]

There could be multiple reasons for this:

• Are you using the correct nixvim branch for your environement? This means that if you are using nixpkgs/nixos/home-manager 23.11 then you need to use the 23.11 branch of nixvim
• If you are using nixpkgs/nixos/home-manager unstable they need to be up-to-date, templ was added on the 21st of december, so you need to have at least this version. Generally we only guarantee that the master of nixvim works with a very recent (not more than a week old) nixpkgs

[psyos10]

Apologies yep, the 23.11 works for me, I was initially confused by why the templ package wasn't there. My nixpkgs isn't that up to date. Thanks.