Expose deeplinks.

[Lukas-Stuehrk]

This change adds links to the name of all members, so it's easy to copy the direct link. This implements #110.

I chose a different approach than adding a chain symbol when hovering the name. The entire name is a link. This leads to some visual changes in the generated documentation. I can change this behavior to the behavior described in the original issue if wanted.

Before the changes:

After the changes when the entire name becomes the link to the anchor:

[mattt]

This is a nice change, @Lukas-Stuehrk!

Before we merge this in, I'd like to give this a quick once-over to get the design a bit closer to what I had in mind with https://github.com/SwiftDocOrg/swift-doc/issues/110#issuecomment-627536084.

[Lukas-Stuehrk]

Thanks! 🙇

Initially, I wanted to build the version as described in #110 and had the current solution as intermediate step. But then I liked the visuals so much that I decided to keep it and go with this solution. I think it looks great and matches the visual language of the index page.