std: uniform modules titles for doc

This commit uniforms the short title of modules provided by libstd,
in order to make their roles more explicit when glancing at the index.

Signed-off-by: Luca Bruno <lucab@debian.org>
Add docs for more crates
Add a compiler-docs target
Fix rustdoc bug involving PatLit
auto merge of #11177 : cmr/rust/native_and_green_docs, r=alexcrichton

Some people have requested this, and I think it's quite useful to have
documentation for the compiler libraries. libnative and libgreen are
self-explanatory I think.
auto merge of #11134 : lucab/rust/lucab/libstd-doc, r=cmr

Uniform the short title of modules provided by libstd, in order to make their roles more explicit when glancing at the index.
Fix a deadlock in a libgreen test

Turns out when you grab an OS mutex, you need to be careful about when and where
things are scheduled!
auto merge of #11204 : alexcrichton/rust/issue-11200, r=cmr

Turns out when you grab an OS mutex, you need to be careful about when and where
things are scheduled!

I've confirmed that I could fairly reliably get a deadlock (1 in 100 times ish) before this, and I cannot get a deadlock after this (after 1000+ runs).

Closes #11200
Update llvm.
auto merge of #11181 : luqmana/rust/up-llvm, r=alexcrichton

No longer need to handle GNUEABIHF and hard floats since LLVM should now choose the right default. Fixes #11164.