relicense shootout-regex-dna.rs

Part of #14248

The authors are @pcwalton and @BurntSushi, and we have their agreement.
update identifier naming warnings to give an example

This updates identifier warnings such as ``struct `foo_bar` should have a
camel case identifier`` to provide an example.

Closes #14738.
Add visit_attribute to Visitor, use it for unused_attribute

The lint was missing a *lot* of cases previously.
Remove the attribute_usage lint

It has been superseded by the unused_attribute lint.

[breaking change]
Improve error message for range in match

Range allows char and numeric types, but previous error message
mentioned only numeric types.
Add back hint for crate level attributes
Remove unused name_str_pair method
auto merge of #14743 : Sawyer47/rust/range-msg, r=huonw

Range allows char and numeric types, but previous error message
mentioned only numeric types.
std::io: expand the oneshot/periodic docs.

Examples!

Fixes #14714.
auto merge of #14728 : TeXitoi/rust/relicense-shootout-regex-dna, r=brson

Part of #14248

The authors are @pcwalton and @BurntSushi, and we have their agreement.

@brson OK?
auto merge of #14741 : sfackler/rust/visit-attr, r=alexcrichton

The lint was missing a *lot* of cases previously.
auto merge of #14745 : huonw/rust/timer-doc, r=alexcrichton

std::io: expand the oneshot/periodic docs.

Examples!

Fixes #14714.
Implement Hash for Bitv and BitvSet

Closes #14744
auto merge of #14749 : sfackler/rust/bitv-hash, r=alexcrichton

Closes #14744
Fix spelling errors in comments.
auto merge of #14751 : jbcrail/rust/fix-comments, r=alexcrichton
relicense shootout-fannkuch-redux.rs

Part of #14248

Main contributors are @pcwalton, @alexcrichton and me.  Only
@dguenther appear in git blame as a minor contribution, but it is
only adding the rust license, so removed by this relicensing.
auto merge of #14756 : TeXitoi/rust/relicense-shootout-fannkuch-redux, r=brson

Part of #14248

Main contributors are @pcwalton, @alexcrichton and me.  Only
@dguenther appear in git blame as a minor contribution, but it is
only adding the rust license, so removed by this relicensing.

@brson OK?
Converted PortReader and ChanWriter to use Vec.
auto merge of #14765 : rapha/rust/master, r=alexcrichton