I have this as a Unix-only API since it seems like Windows doesn't have
a similar API.

This makes it more robust when assertions are disabled,
crashing instead of causing UB.

Also introduces a tidy check to enforce this rule,
which in turn necessitated making tidy run on src/rustllvm.

Fixes rust-lang#44020

impl From for Mutex and RwLock

I felt that these implementations were missing, because doing `x.into()` works for other smart containers (such as `RefCell`), and in general I would say that the conversion makes sense.

add doc for doing `Read` from `&str`

This information can be found on [stackoverflow](https://stackoverflow.com/questions/32674905/pass-string-to-function-taking-read-trait) but I think it would be beneficial if it was documented in the `Read` trait itself.

I had an *extremely* hard time finding this information, and "mocking" a reader with a string is an EXTREMELY common thing (I believe).

Add process::parent_id

I have this as a Unix-only API since it seems like Windows doesn't have
a similar API.

r? @alexcrichton

Fixes spelling error in COMPILER_TESTS.md

Fixes a small spelling mistake :P

Fix typo in MIR "cannot move out of borrowed content"

I believe this all we need to change (rust-lang#46018). Anyway, do let me know if there is anything else that needs to changed as well!

Print the address of the pointed value in Pointer impl for Rc and Arc

Fixes rust-lang#35384

Fix some docs summary nits

[rustllvm] Use report_fatal_error over llvm_unreachable

This makes it more robust when assertions are disabled, crashing instead of causing UB.

Also introduces a tidy check to enforce this rule, which in turn necessitated making tidy run on `src/rustllvm`.

Fixes rust-lang#44020

Fix doc tests for trim_right_matches

First pr, but isn't anything big so hopefully it should all be good.