Rename `overrides` to `package` in profiles.

Renaming per the discussion at rust-lang/rust#48683 (comment).

I left backwards-compatibility in case anyone is using it, since it required very little effort.

cc @da-x, FYI.

…chton

Update cargo, cc, books

Update `cc` to include new parallel building support.

## nomicon

3 commits in 4374786f0b4bf0606b35d5c30a9681f342e5707b..5004ad30d69f93553ceef74439fea2159d1f769e
2019-09-17 18:33:21 +0200 to 2019-10-12 19:52:40 +0200
- further clarify C11 and C/C++11 terminology (rust-lang/nomicon#169)
- atomics: C11 -> C++20 (rust-lang/nomicon#168)
- use sound/unsound terminology

## cargo

12 commits in a429e8cc4614a46a86322a0777a477e2baa83f1c..3a9abe3f065554a7fbc59f440df2baba4a6e47ee
2019-10-04 17:36:12 +0000 to 2019-10-15 15:55:35 +0000
- Fix typo in git index initialization error path (rust-lang/cargo#7512)
- Reject feature flags in a virtual workspace. (rust-lang/cargo#7507)
- Rename `overrides` to `package` in profiles. (rust-lang/cargo#7504)
- Allow publishing with dev-dependencies without a version. (rust-lang/cargo#7333)
- Stabilize cache-messages (rust-lang/cargo#7450)
- don't lock the package cache when cleaning target dir. (rust-lang/cargo#7502)
- Document rustc wrapper (rust-lang/cargo#7499)
- Migrate towards exclusively using serde for `Config` (rust-lang/cargo#7456)
- Re-enable some MSVC tests. (rust-lang/cargo#7492)
- when -Z unstable-options not specified, don't validate --profile (rust-lang/cargo#7489)
- Improve error message for cyclic dependencies (rust-lang/cargo#7470)
- Some minor clippy fixes. (rust-lang/cargo#7484)

## book

7 commits in 04806c80be0f54b1290287e3f85e84bdfc0b6ec7..9bb8b161963fcebc9d9ccd732ba26f42108016d5
2019-10-01 20:20:22 -0400 to 2019-10-14 18:42:55 -0500
- Make a portion of text less ambiguous (rust-lang/book#2092)
- fix heading level (rust-lang/book#2117)
- Add missing "of" before `"duck typing"`. (rust-lang/book#1951)
- ch18-03: no need to debug print destructured int (rust-lang/book#1991)
- Subtle fix to introduce ? on Option in Chapter 9.2 (rust-lang/book#2047)
- make wording clearer (rust-lang/book#1976)
- Update the version of rand we use

## rust-by-example

5 commits in a6288e7407a6c4c19ea29de6d43f40c803883f21..0b111eaae36cc4b4997684be853882a59e2c7ca7
2019-10-01 10:09:14 -0300 to 2019-10-14 18:34:25 -0300
- Some fix to three files (rust-lang/rust-by-example#1280)
- Add reference to Generics (rust-lang/rust-by-example#1281)
- Confusing and long sentence (rust-lang/rust-by-example#1282)
- Explicit mention of slice range meaning (rust-lang/rust-by-example#1277)
- Updated aliasing for nll (rust-lang/rust-by-example#1276)

Update cargo, books

## nomicon

3 commits in 4374786f0b4bf0606b35d5c30a9681f342e5707b..5004ad30d69f93553ceef74439fea2159d1f769e
2019-09-17 18:33:21 +0200 to 2019-10-12 19:52:40 +0200
- further clarify C11 and C/C++11 terminology (rust-lang/nomicon#169)
- atomics: C11 -> C++20 (rust-lang/nomicon#168)
- use sound/unsound terminology

## cargo

12 commits in a429e8cc4614a46a86322a0777a477e2baa83f1c..3a9abe3f065554a7fbc59f440df2baba4a6e47ee
2019-10-04 17:36:12 +0000 to 2019-10-15 15:55:35 +0000
- Fix typo in git index initialization error path (rust-lang/cargo#7512)
- Reject feature flags in a virtual workspace. (rust-lang/cargo#7507)
- Rename `overrides` to `package` in profiles. (rust-lang/cargo#7504)
- Allow publishing with dev-dependencies without a version. (rust-lang/cargo#7333)
- Stabilize cache-messages (rust-lang/cargo#7450)
- don't lock the package cache when cleaning target dir. (rust-lang/cargo#7502)
- Document rustc wrapper (rust-lang/cargo#7499)
- Migrate towards exclusively using serde for `Config` (rust-lang/cargo#7456)
- Re-enable some MSVC tests. (rust-lang/cargo#7492)
- when -Z unstable-options not specified, don't validate --profile (rust-lang/cargo#7489)
- Improve error message for cyclic dependencies (rust-lang/cargo#7470)
- Some minor clippy fixes. (rust-lang/cargo#7484)

## book

7 commits in 04806c80be0f54b1290287e3f85e84bdfc0b6ec7..9bb8b161963fcebc9d9ccd732ba26f42108016d5
2019-10-01 20:20:22 -0400 to 2019-10-14 18:42:55 -0500
- Make a portion of text less ambiguous (rust-lang/book#2092)
- fix heading level (rust-lang/book#2117)
- Add missing "of" before `"duck typing"`. (rust-lang/book#1951)
- ch18-03: no need to debug print destructured int (rust-lang/book#1991)
- Subtle fix to introduce ? on Option in Chapter 9.2 (rust-lang/book#2047)
- make wording clearer (rust-lang/book#1976)
- Update the version of rand we use

## rust-by-example

5 commits in a6288e7407a6c4c19ea29de6d43f40c803883f21..0b111eaae36cc4b4997684be853882a59e2c7ca7
2019-10-01 10:09:14 -0300 to 2019-10-14 18:34:25 -0300
- Some fix to three files (rust-lang/rust-by-example#1280)
- Add reference to Generics (rust-lang/rust-by-example#1281)
- Confusing and long sentence (rust-lang/rust-by-example#1282)
- Explicit mention of slice range meaning (rust-lang/rust-by-example#1277)
- Updated aliasing for nll (rust-lang/rust-by-example#1276)

…age`

It was renamed in <rust-lang/cargo#7504>.

230: Updated documentation on profile-overrides r=therealprof a=irwineffect

Profile-overrides has now been stabilized (rust-lang/cargo#7591), so the book has been updated to point to the stable documentation.

During stabilization, syntax was changed to use "package" instead of "overrides" (rust-lang/cargo#7504), documentation updated to match.

Co-authored-by: James Irwin <irwineffect@gmail.com>

The unstable feature has changed the naming scheme
of the toml keys. For more info, see: rust-lang/cargo#7504