…r=SimonSapin

Implement ExactSizeIterator for ToLowercase and ToUppercase

Rollup of 11 pull requests

Successful merges:

 - #56348 (Add todo!() macro)
 - #57729 (extra testing of how NLL handles wildcard type `_`)
 - #57847 (dbg!() without parameters)
 - #58778 (Implement ExactSizeIterator for ToLowercase and ToUppercase)
 - #58812 (Clarify distinction between floor() and trunc())
 - #58939 (Fix a tiny error in documentation of std::pin.)
 - #59116 (Be more discerning on when to attempt suggesting a comma in a macro invocation)
 - #59252 (add self to mailmap)
 - #59275 (Replaced self-reflective explicit types with clearer `Self` or `Self::…` in stdlib docs)
 - #59280 (Stabilize refcell_map_split feature)
 - #59290 (Run branch cleanup after copy prop)

Failed merges:

r? @ghost

Version 1.35.0 (2019-05-23)
==========================

Language
--------
- [`FnOnce`, `FnMut`, and the `Fn` traits are now implemented for `Box<FnOnce>`,
  `Box<FnMut>`, and `Box<Fn>` respectively.][59500]
- [You can now coerce closures into unsafe function pointers.][59580] e.g.
  ```rust
  unsafe fn call_unsafe(func: unsafe fn()) {
      func()
  }

  pub fn main() {
      unsafe { call_unsafe(|| {}); }
  }
  ```


Compiler
--------
- [Added the `armv6-unknown-freebsd-gnueabihf` and
  `armv7-unknown-freebsd-gnueabihf` targets.][58080]
- [Added the `wasm32-unknown-wasi` target.][59464]


Libraries
---------
- [`Thread` will now show its ID in `Debug` output.][59460]
- [`StdinLock`, `StdoutLock`, and `StderrLock` now implement `AsRawFd`.][59512]
- [`alloc::System` now implements `Default`.][59451]
- [Expanded `Debug` output (`{:#?}`) for structs now has a trailing comma on the
  last field.][59076]
- [`char::{ToLowercase, ToUppercase}` now
  implement `ExactSizeIterator`.][58778]
- [All `NonZero` numeric types now implement `FromStr`.][58717]
- [Removed the `Read` trait bounds
  on the `BufReader::{get_ref, get_mut, into_inner}` methods.][58423]
- [You can now call the `dbg!` macro without any parameters to print the file
  and line where it is called.][57847]
- [In place ASCII case conversions are now up to 4× faster.][59283]
  e.g. `str::make_ascii_lowercase`
- [`hash_map::{OccupiedEntry, VacantEntry}` now implement `Sync`
  and `Send`.][58369]

Stabilized APIs
---------------
- [`f32::copysign`]
- [`f64::copysign`]
- [`RefCell::replace_with`]
- [`RefCell::map_split`]
- [`ptr::hash`]
- [`Range::contains`]
- [`RangeFrom::contains`]
- [`RangeTo::contains`]
- [`RangeInclusive::contains`]
- [`RangeToInclusive::contains`]
- [`Option::copied`]

Cargo
-----
- [You can now set `cargo:rustc-cdylib-link-arg` at build time to pass custom
  linker arguments when building a `cdylib`.][cargo/6298] Its usage is highly
  platform specific.

Misc
----
- [The Rust toolchain is now available natively for musl based distros.][58575]

[59460]: rust-lang/rust#59460
[59464]: rust-lang/rust#59464
[59500]: rust-lang/rust#59500
[59512]: rust-lang/rust#59512
[59580]: rust-lang/rust#59580
[59283]: rust-lang/rust#59283
[59451]: rust-lang/rust#59451
[59076]: rust-lang/rust#59076
[58778]: rust-lang/rust#58778
[58717]: rust-lang/rust#58717
[58369]: rust-lang/rust#58369
[58423]: rust-lang/rust#58423
[58080]: rust-lang/rust#58080
[57847]: rust-lang/rust#57847
[58575]: rust-lang/rust#58575
[cargo/6298]: rust-lang/cargo#6298
[`f32::copysign`]: https://doc.rust-lang.org/stable/std/primitive.f32.html#method.copysign
[`f64::copysign`]: https://doc.rust-lang.org/stable/std/primitive.f64.html#method.copysign
[`RefCell::replace_with`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.replace_with
[`RefCell::map_split`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.map_split
[`ptr::hash`]: https://doc.rust-lang.org/stable/std/ptr/fn.hash.html
[`Range::contains`]: https://doc.rust-lang.org/std/ops/struct.Range.html#method.contains
[`RangeFrom::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeFrom.html#method.contains
[`RangeTo::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeTo.html#method.contains
[`RangeInclusive::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.contains
[`RangeToInclusive::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeToInclusive.html#method.contains
[`Option::copied`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.copied