Rollup merge of rust-lang#70064 - ehuss:update-books, r=ehuss

Update books

## reference

4 commits in 559e09c..e2f11fe
2020-03-02 01:17:14 +0100 to 2020-03-10 06:59:24 +0100
- Update rustc-guide to rustc-dev-guide (rust-lang/reference#777)
- Fix expression and statement grammar. (rust-lang/reference#776)
- Fix grammar for tuple struct patterns. (rust-lang/reference#775)
- A typo? (rust-lang/reference#770)

## rust-by-example

3 commits in db57f899ea2a56a544c8d280cbf033438666273d..cb369ae95ca36b841960182d26f6d5d9b2e3cc18
2020-02-18 17:46:46 -0300 to 2020-03-14 12:13:22 -0500
- Use rust-lang/rust linkchecker on CI. (rust-lang/rust-by-example#1310)
- Rewrite freeze.md (rust-lang/rust-by-example#1314)
- Clarify type suffixing with example (rust-lang/rust-by-example#1312)

## embedded-book

2 commits in b81ffb7a6f4c5aaed92786e770e99db116aa4ebd..d22a9c487c78095afc4584f1d9b4ec43529d713c
2020-02-27 08:06:04 +0000 to 2020-03-04 09:46:30 +0000
- Updated documentation on profile-overrides  (rust-embedded/book#230)
- Update information on Cargo `profile-overrides`  (rust-embedded/book#229)