feat(lsp): Support gotoDefinition from go->templ

[tris203]

Support goToDefinition from a go file to a templ file.

Steps to test:

1. Attach both gopls and templ lsp to a main.go buffer
2. GoToDefinition
3. Profit

Caveats, because gopls and templ are attached, both references will be returned. Editor settings can be used to set preference to select from a list or go to the preferred option (probably the templ file)

When and if this was merged, it would need further adjustments to neovim/lspconfig to attach templ to go files too and would probably need a change in the vscode extension for the same

Closes #387

[joerdav]

Sorry for a delay on this one. This is a great addition, many have said a pain point is gotodefinition from go to templ and this is the first step!

Editor settings can be used to set preference to select from a list or go to the preferred option (probably the templ file)

I wonder if we should add the docs for how to do the above along side this change?

[a-h]

I looked at this the other day, and couldn't get it to work. Probably because I hadn't told my editor to use the templ LSP for Go files too, so I'd say we do need to do that.

[tris203]

I have done it in my config for neovim, when it comes to other editors:

Neovim: lspconfig change
VSCode: I assume an extension change

helix/emacs, will need PRs to the relevant repos

Am i missing anything?

[joerdav]

I think that's correct yes. If we just update those things and there are no user config changes required apart from updating configs then maybe it's okay to merge this now at this point? Then we can gradually update the extensions etc?