docs: add neovim setup section to adev

[shannonvc]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular/blob/main/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• angular.io application / infrastructure changes
• Other... Please describe:

What is the current behavior?

It seems like the language-service Neovim setup was lost in migration from aio to adev.

Issue Number: #56055

What is the new behavior?

Neovim setup section that was in aio was added back to adev.

Does this PR introduce a breaking change?

• Yes
• No

[AndrewKushnir]

It'd be hard to keep this instruction up-to-date. Would it be possible to have that instruction as a part of one of the mentioned repository and just link to that page?

[shannonvc]

The PR currently brings back the page as it existed on aio

That instruction is just extracted from the 2nd link, which is an issue on the coc-angular plugin repo. It seems like that repo isn't really maintained since Angular 16, hence the issue.

I have tried looking for angular instructions in the coc.nvim repository but couldn't find anything.

I can try to find an alternative but it may take a while as I am not familiar with Neovim myself.

[shannonvc]

I pushed an update which rewrites the Neovim section to use the nvim-lspconfig plugin instead of coc.

It lives under the neovim organization directly. It also allowed me to simply link to their install instruction and angularls configuration pages.