Odoc and eio

[jonludlam]

Add in patched versions of odoc (including all related packages) and eio, as it was needed for odoc driver. Also add in a patch for ocaml-lsp-server so it compiles with the latest odoc-parser.

The version of odoc here is just the master commit on oxcaml/odoc for now, with all of Luke's patches, plus one more to make sherlodoc happy.

The eio patch came from @avsm and I've tested it as far as using it to run odoc_driver, but no further!

[avsm]

Rather than keeping patch files, you can just point the url directly to a git+https:// branch (with a direct checksum). This is far easier to maintain as you dont have to generate the patch files for here, and updates are eaier too.

[jonludlam]

Rather than keeping patch files, you can just point the url directly to a git+https:// branch (with a direct checksum). This is far easier to maintain as you dont have to generate the patch files for here, and updates are eaier too.

Yes, I thought about that. The odoc packages are all using tarballs direct from github similar to what you're suggesting - but that's because they're fetching from the odoc repo in the oxcaml org. I've gone with upstream URLs + patches for now for eio as there's no handy fork in the oxcaml org and I was reluctant to point to your fork directly - perhaps I'm being too fussy though? I'm just worried that it'll get confusing if we end up switching source URLs whenever someone has a new change to add in.

[avsm]

In my view, pointing to my fork directly is fine, and changing source URLs is fine. This is a fast moving and unversioned ecosystem right now.

[jonludlam]

OK, I'll update this PR and the MDX one to get the code direct from a repo.

[jonludlam]

I think this is ready to go now.