Update documentation for from_raw_parts

Fixes #19269.
Lifetime guide -> ownership guide
impl Clone for Cow
small doc fixes

We don't need this &mut, and vec could use []s
Add test for #18908
fix expand_quote_ty function as parse_ty was changed and needs no arguments now
Fix typo in reference.md
Replace some verbose match statements with their `if let` equivalent.

No semantic changes, no enabling `if let` where it wasn't already enabled.
Allow trailing commas in array patterns and attributes
Simplify `RefCell` code a bit, make `deref` a no-op.
allow macro expansions in attributes
std: Remove implicit shrinking from hash_map.

Implements fn shrink_to_fit for HashMap.
std: Change the behavior of `reserve` for HashMap.

HashMap's `reserve` method now takes as an argument the *extra* space
to reserve.

[breaking-change]
fix missed switch pointed out in review plus a few others
std: add tests for the Vec<u8> Writer impl
std: add Reader impl for &[u8]
Add test for expanding doc strings in macros.
rustdoc: Use relative paths in source renders.

Before: doc/src/collections/home/lifthrasiir/git/rust/src/libcollections/vec.rs.html
After: doc/src/collections/vec.rs.html

If the source code is in the parent dirs relative to the crate root,
`..` is replaced with `up` as expected. Any other error like non-UTF-8
paths or drive-relative paths falls back to the absolute path.

There might be a way to improve on false negatives, but this alone
should be enough for fixing #18370.
added negative test for macro expansion in attributes
auto merge of #19436 : lifthrasiir/rust/rustdoc-short-src-paths, r=alexcrichton

Before: `doc/src/collections/home/lifthrasiir/git/rust/src/libcollections/vec.rs.html`
After: `doc/src/collections/vec.rs.html`

If the source code is in the parent dirs relative to the crate root, `..` is replaced with `up` as expected. Any other error like non-UTF-8 paths or drive-relative paths falls back to the absolute path.

There might be a way to improve on false negatives, but this alone should be enough for fixing #18370.