doc.rust-lang.org front page should have a search box

[kmcallister]

It should act like the search box on API pages, and we would add the various guides / references / etc. to the list of possible search results. (And maybe the names of individual sections in the guides?)

This would remove the need for two browser bookmarks, and generally make the docs more integrated and easier to navigate.

We could move the current front page to contents.html. The new front page would have just a centered, focus-on-load search box, with a few links below -- the same set as the Docs column on http://www.rust-lang.org/.

cc @steveklabnik

[huonw]

cc #14572

[reem]

Personally this is a huge pain point as I find myself autocompleting to doc.rust-lang.org when really what I want is doc.rust-lang.org/std. Having a search box on doc.rust-lang.org would mostly solve this problem.

[Gankra]

cc me

[zonyitoo]

Maybe the contents of doc.rust-lang.org/std should be merged into doc.rust-lang.org, or just replace it.

[steveklabnik]

This is a dup of #14572 and so I'm closing. Would love to have it though!