impl Clone for Cow
small doc fixes

We don't need this &mut, and vec could use []s
fix expand_quote_ty function as parse_ty was changed and needs no arguments now
Fix typo in reference.md
Allow trailing commas in array patterns and attributes
Simplify `RefCell` code a bit, make `deref` a no-op.
rustdoc: Check for href when prepending rootPath

Fixes #18354.
better wording
replace 'but' with 'and'
Improve documentation of checked_* functions
Update comment to current file path for intrinsics
lldb: Fix pretty printer for nullable-opt enums with fat pointers.
gdb: Fix pretty printer for nullable-opt enums with fat pointers.
Fixed out of date comment on `copy_memory`
libtest: get rid of dependency to ToJson

deriving encodable + using json::PrettyEncoder removes the only ToJson trait implementation in the rust repository outside of libserialize
Remove outdated comment.

https://github.com/rust-lang/rust/pull/19472#issuecomment-65370278
rustdoc: Fixed a missing rendering of ForeignStaticItems.
rustdoc: Refactored various uses of ItemType.

In particular, ItemType variants are no longer reexported. Since
we already do namespace them via `item_type` mod, it's fine.
rustdoc: Removed Foreign{Function,Static} item types.

They are just (unsafe) functions and static items to most users
and even compilers! The metadata doesn't distinguish them, so Rustdoc
ended up producing broken links (generated `ffi.*.html`, links to
`fn.*.html`). It would be best to avoid this pitfall at all.
rustdoc: Avoid rendering foreign items to the sidebar.

Otherwise the generated documentation is 30% larger. The sidebar
renders an entry for each item to all items, so large modules have
O(n^2) items rendered in the sidebars. Not a correct solution, but
at least it works.