Index is missing from fish shell docs

[andreiborisov]

Hi! First of all, thank you so much for such an awesome tool!☺️

I'm trying to generate a docset for fish shell.

Built docs: https://fishshell.com/docs/current/index.html
Src: https://github.com/fish-shell/fish-shell/tree/master/doc_src

I've built docs from source locally, but unfortunately, the index doesn't seem to work:

❯ doc2dash ./fish
Converting intersphinx docs from "fish" to "./fish.docset".
Parsing documentation...
Added 0 index entries.

[hynek]

I'm afraid the problem is that the fish docs don't provide any symbols whatsoever. Check out this for example: https://raw.githubusercontent.com/fish-shell/fish-shell/master/doc_src/cmds/abbr.rst

So I'm afraid there simply is no index that doc2dash could use.

[andreiborisov]

Thanks! I’ll try to get the PR going in fish repo then.