Rustdoc output slightly nondeterministic

[sfackler]

There's a bit of nondeterminism in rustdoc output across runs even when the source doesn't change: rust-openssl/rust-openssl@1cb83ff I'm guessing it's due to randomized HashMap iteration order.

It'd be nice to switch to a non keyed Hasher or maybe just TreeMaps in rustdoc to avoid "phantom" documentation updates.

May be as easy as changing HashMap to rustc::util::FnvHashMap in https://github.com/rust-lang/rust/blob/master/src/librustdoc/html/render.rs.

[Gankra]

Using @jakub-'s solution barring catastrophe

[sfackler]

This still appears to be present in other contexts than the one that was fixed: rust-openssl/rust-openssl@bca2a36