I often have to run `ast-json` or look into the pretty-printer source to figure out what the fields of an AST enum mean. I've tried to document most of what I know (and some semi-obvious stuff).

r? @steveklabnik

f? @EddyB

 Fixes #21589

 Fixes #22309

I am pretty sure that this is the right way to do this, given the other macros, but I'm not 100% sure.

 This is a significant performance problem in Servo.

r? @brson

 Typo

 And do some formatting while I'm here.

 Update documentation to reflect #21824.

r? @steveklabnik

 unbreak openbsd/bitrig build
- remove `pub` from `struct` (error: visibility has no effect inside functions)
- move `pthread_main_np` into function

r? @alexcrichton

 r? @steveklabnik

 r? @aturon

 Require braces when a closure has an explicit return type. This is a [breaking-change]: instead of a closure like `|| -> i32 22`, prefer `|| -> i32 { 22 }`.

Fixes #23420.

Fixes #21589

Fixes #22309

This is a significant performance problem in Servo.

Typo

Fixes #22927

 Nothing inside of the read/write interface itself can panic, so any
poison must have been the result of user code which the lock isn't
protecting.

This seems safe to me, but if we don't want to go this route we should update the docs to indicate that these methods can panic.

r? @alexcrichton

 This commit stabilizes the `cloned` iterator after tweaking the signature to
require that the iterator is over `&T` instead of `U: Deref<T>`. This method has
had time to bake for awhile now and it's not clear whether the `Deref` bound is
worth it. Additionally, there aren't clear conventions on when to bound and/or
implement the `Deref` trait, so for now the conservative route is to require
references instead of `U: Deref<T>`.

To change this signature to using `Deref` would technically be a
backwards-incompatible change, but it is doubtful that any code will actually
break in practice.

 Hopefully didn’t miss or mess up anything.

~~EDIT: ah, as usual, just didn’t bother running build before pushing a submit request button. Build pending.~~

[breaking-change]: instead of a closure like `|| -> i32 22`, prefer `||
-> i32 { 22 }`.

Fixes #23420.

 I often have to run `ast-json` or look into the pretty-printer source to figure out what the fields of an AST enum mean. I've tried to document most of what I know (and some semi-obvious stuff).

r? @steveklabnik

f? @EddyB

 The alignment field is actually a \"pointer sized\" type instead of always i64,
requiring that the size of the padding field is also calculated slightly
differently.

Closes #23425

 Very minor fix: in `std::net::Ipv6Addr::new`, the documentation had an incomplete representation of the resulting address, missing the last two groups.

 Since module `std::sync::mpsc` is stable now, fix the deprecated link `comm` with `sync::mpsc`.

 Closes #23451.

 This commit clarifies some of the unstable features in the `str` module by
moving them out of the blanket `core` and `collections` features.

The following methods were moved to the `str_char` feature which generally
encompasses decoding specific characters from a `str` and dealing with the
result. It is unclear if any of these methods need to be stabilized for 1.0 and
the most conservative route for now is to continue providing them but to leave
them as unstable under a more specific name.

* `is_char_boundary`
* `char_at`
* `char_range_at`
* `char_at_reverse`
* `char_range_at_reverse`
* `slice_shift_char`

The following methods were moved into the generic `unicode` feature as they are
specifically enabled by the `unicode` crate itself.

* `nfd_chars`
* `nfkd_chars`
* `nfc_chars`
* `graphemes`
* `grapheme_indices`
* `width`