Add a b'x' byte literal of type u8.
Add a b"xx" byte string literal of type &'static [u8].
Add br##"xx"## raw byte string literals.
Document the byte, byte string, and raw byte string literals.
Refactor backslash-escape parsing to share similar code.

Move into a new syntax::parse::lexer::StringReader method the code
that was almost duplicated for parsing backslash-escapes in
byte, byte string, char, and string literals.
Fix some violations of stronger guarantees for mutable borrows.

See 159e27aebb940926ccf1bad0b2b12087d36ad903
Fix expected error message in a test.

The change is a result of the char/string parsing refactor.
emacs: Don't overwrite font lock for attributes

This addresses the font lock regression introduced by the earlier pull
request #14818 - attributes are no longer be highligted inside of comments
and strings.

Also add some font lock test infrastructure and some tests for attribute
font locking.
emacs: Add shebang to test script
emacs: Remove outdated references to ~ in tests
auto merge of #14880 : SimonSapin/rust/byte-literals, r=alexcrichton

See #14646 (tracking issue) and rust-lang/rfcs#69.

This does not close the tracking issue, as the `bytes!()` macro still needs to be removed. It will be later, after a snapshot is made with the changes in this PR, so that the new syntax can be used when bootstrapping the compiler.
Wrap debuginfo.rs at 80 columns.

Plus a few other misc style things.
change ~[] -> Vec for collect()

This updates the documentation for result::collect() and
option::collect() to use the new-style syntax for vectors, instead of
the old ~[].

Also updates the code blocks for these docs so they will be tested
automatically.

closes #14991
auto merge of #14992 : nathantypanski/rust/collect-docs, r=huonw

This updates the documentation for result::collect() and
option::collect() to use the new-style syntax for owned pointers and
vectors.

closes #14991
fix signatures of mmap-related functions from libc
rustdoc: Fix testing indented code blocks

The collapse/unindent passes were run in the wrong order, generating different
markdown for indented tests.
rustdoc: Don't inject `extern crate std`.

No need to duplicate the compiler's work!

Closes #14999
std: Remove dual export of `Show`

Closes #14996
auto merge of #14994 : nick29581/rust/comments, r=bstrie

Plus a few other misc style things.
auto merge of #15000 : alexcrichton/rust/fix-rustdoc-tests, r=huonw

Commits have the descriptions.