Fix invalid links when served with trailing slash

[eddsby]

The Issue:

Visit this URL directly: https://docs.darklang.com/contributing/getting-started
301 Redirects to (note trailing slash): https://docs.darklang.com/contributing/getting-started/

The internal links on this page are now invalid, for example - https://docs.darklang.com/contributing/getting-started/if-you-dont-know-ocaml

if-you-dont-know-ocaml is getting appended to https://docs.darklang.com/contributing/getting-started/

If you navigate to this page through JS, avoiding the 301 redirect and actually arriving at https://docs.darklang.com/contributing/getting-started (no trailing slash) then if-you-dont-know-ocaml is getting appended to https://docs.darklang.com/contributing/ and the link is correct.

I encountered this by navigating to the contributor docs from the dark README link, https://darklang.github.io/docs/contributing/getting-started, which ultimately leaves you on the trailing slash page with invalid links.

See some discussion here - facebook/docusaurus#3372 and facebook/docusaurus#5250.

The simplest fix seems to be linking directly to documents instead of using URL paths, as I have applied here for just the contributing pages.

There is a trailingSlash added from version 2.0.0-beta.df8a900f9 onwards, however upgrading to this seemed to have numerous breaking changes.

[pbiggar]

Very helpful thanks! I didn't know you could link to files - TIL.

There are a few linting errors in CI that you can see here - I'll merge as soon as it goes green.

[eddsby]

I'm getting those same linting errors on the main branch, I don't think they're related to this change. I could look at fixing though

[pbiggar]

Oh, that makes sense - I've been pushing to main a bit 😬