Change RDoc docs path

[andyw8]

Motivation

We're considering a new Documentation site (https://github.com/Shopify/ruby-lsp/pull/2233). Let's rename the RDoc output directory so that we can use /docs for the new one.

Implementation

Change output directory, update .gitignore.

Automated Tests

n/a

Manual Tests

Run bundle exec rake rdoc verify the docs are generated in rdoc_docs, but git ignored.

[andyw8]

We'll also need to update the GitHub Pages path in https://github.com/Shopify/ruby-lsp/settings/pages

[andyw8]

Ah, yeah, that seems to be an annoying limitation.

I see some workarounds to use other directories, such as this action.

But I wonder if we could just change publish_docs.yml so that it renames the directory before pushing to the gh-pages branch. 🤔

[vinistock]

Given that the docs directory and all of its contents are generated, I think simply deleting the it and running rdoc would probably do the trick.

Can we not push the new docs in one go though? Is there too much configuration/customization that has to happen ahead of time?

[andyw8]

Closing until we determine the wider approach for new docs.