fixes rust-lang#47639

This path was considered to be unreachable. However,
`&mut` could potentially live inside `static`.
For example, `static TAB: [&mut [u8]; 0] = [];`.

This text was copy-pasted from the `AsRef` docs to `AsMut`, but needed
some additional adjustments for correctness.

Includes rust-lang/book#1088 and
rust-lang/book@62210e3

and improve printing of errors

When looking up a field defintion, since the name might be incorrect in the field init shorthand case.

cc rust-lang/rls#699

…6026

Make inline assembly volatile if it has no outputs. Fixes rust-lang#46026

…estebank

add documentation from doc(include) to analysis data

cc rust-lang#44732

Currently save-analysis only loads docs from plain doc comments and doc attributes. Since `#[doc(include="filename.md")]` doesn't create a plain doc attribute when it loads the file, we need to be sure to pick up this info for the analysis data.

…akis

Disallow mutable borrow to non-mut statics

Closes rust-lang#42344.

Add a regression test for rust-lang#44415

This PR adds a regression test for issue rust-lang#44415.

Fixes rust-lang#44415.

…chton

Update book

This PR does two things:

1. update the book to include rust-lang/book#1088
2. update to mdbook 0.1

Both of these things are big changes, so I want to land them now, well before the next branch, so we can kick the tires.

------------------------------

Locally, I'm seeing some weirdness around the reference and this:

![image](https://user-images.githubusercontent.com/27786/35411917-8dcbb31a-01e8-11e8-8c30-0bd280d93b9d.png)

Putting this PR up so others can try and build and see if it reproduces for them.

…eveklabnik

Make wording around 0-cost casts more precise

…ilize, r=petrochenkov

Stabilize use_nested_groups

As requested in rust-lang#44494. Documentation PRs already sent.

…ulacrum

Fix rustdoc ICE on macros defined within functions

fixes rust-lang#47639

Fix info about generic impls in AsMut docs

This text was copy-pasted from the `AsRef` docs to `AsMut`, but needed some additional adjustments for correctness.

save-analysis: avoid implicit unwrap

When looking up a field defintion, since the name might be incorrect in the field init shorthand case.

cc rust-lang/rls#699

r? @eddyb