Rollup merge of #76764 - ehuss:update-books, r=ehuss

Update books

## nomicon

1 commits in 25854752549d44d76fbd7650e17cb4f167a0b8fb..6e57e64501f61873ab80cb78a07180a22751a5d6
2020-08-19 16:41:48 -0400 to 2020-09-14 11:40:23 -0400
- Fix API change to alloc::Global::grow. (rust-lang-nursery/nomicon#236)

## reference

3 commits in 25391dba46262f882fa846beefaff54a966a8fa5..56a13c082ee90736c08d6abdcd90462517b703d3
2020-09-02 07:22:55 -0700 to 2020-09-14 23:20:16 -0700
- Update the description of staticlib (rust-lang-nursery/reference#884)
- Rust 1.46 now allows more features in const fn (rust-lang-nursery/reference#883)
- Document the enum changes in RFC 2195 (rust-lang-nursery/reference#879)

## book

1 commits in e5ed97128302d5fa45dbac0e64426bc7649a558c..cb28dee95e5e50b793e6ba9291c5d1568d3ad72e
2020-08-31 12:53:40 -0500 to 2020-09-09 10:06:00 -0500
- Fixed the error message of invalid array element access in ch03.2 (rust-lang/book#2446)