doc.crates.io no HTTPS

[TomasHubelbauer]

While crates.io seem to support HTTPS (and do upgrade HTTP requests to it), doc.crates.io doesn't and thus doesn't, respectively. This displays Not secure in Google Chrome 62.

[carols10cents]

Yep, this is a duplicate of #621. Currently, doc.crates.io is hosted on github pages, so we're unable to use a custom domain+SSL.

In the near future, we will be switching to serving cargo docs from https://doc.rust-lang.org/cargo, and we will have SSL configured there. You can track the progress of that effort at rust-lang/rust#44910.

In the meantime, the workaround is to visit http://doc.crates.io instead. Thank you for your patience!