Ex_doc: Links to functions containing `&` characters do not fully work

[archdragon]

Links to functions containing & will direct to the top of the module page (instead of scrolling to the relevant function description).

Took a quick look at it and from what I can see this happens because we're getting & in the hash/link and just & in the anchor.

To reproduce:

1. Go to https://hexdocs.pm/elixir/Function.html
2. Click on &/1

Current behaviour: You are being redirected to the top of the SpecialForms module page
Expected behaviour: You are being redirected to the top of the &/1 function description on the SpecialForms module page

[eksperimental]

I can look into it.

[eksperimental]

And thank you for the report.

[archdragon]

Thanks @eksperimental ! (it's awesome that I've mentioned an issue just before going to sleep and when I woke up it's already fixed :D )