Sort most attributes alphabetically
Replace all references to "Win32" with "Windows".

For historical reasons, "Win32" has been used in Rust codebase to mean "Windows OS in general".
This is confusing, especially now, that Rust supports Win64 builds.

[breaking-change]
Replace #[cfg(target_os = "win32")] with #[cfg(target_os = "windows")]
Minor changes to `rust.md`, and `guide-ffi.md`.

  * `rust.md`: whanges for consistency

  * `guide-ffi.md`: wrapped inline code
Replace "ignore-win32" in tests with "ignore-windows"
~ -> Box in the manual

Fixes #16439
libcore: rename private cmp macros

eq_impl! => partial_eq_impl!
totaleq_impl! => eq_impl!
ord_impl! => partial_ord_impl!
totalord_impl! => ord_impl!
std: Rename various slice traits for consistency

ImmutableVector -> ImmutableSlice
ImmutableEqVector -> ImmutableEqSlice
ImmutableOrdVector -> ImmutableOrdSlice
MutableVector -> MutableSlice
MutableVectorAllocating -> MutableSliceAllocating
MutableCloneableVector -> MutableCloneableSlice
MutableOrdVector -> MutableOrdSlice

These are all in the prelude so most code will not break.

[breaking-change]
std: Rename slice::Vector to Slice

This required some contortions because importing both raw::Slice
and slice::Slice makes rustc crash.

Since `Slice` is in the prelude, this renaming is unlikely to
casue breakage.

[breaking-change]
core: Rename ImmutableSlice::unsafe_ref to unsafe_get

Deprecate the previous.
core: Deprecate ImmutableSlice::tailn and initn

These are equivalent to slice_from and slice_to.
core: Rename MutableCloneableSlice::copy_from to clone_from_slice

Deprecate the previous.
collections: Deprecate Vec::tailn. Same as slice_from
core: Rename ImmutableEqSlice to ImmutablePartialEqSlice

This is in the prelude and won't break much code.

[breaking-change]
core: Add binary_search and binary_search_elem methods to slices.

These are like the existing bsearch methods but if the search fails,
it returns the next insertion point.

The new `binary_search` returns a `BinarySearchResult` that is either
`Found` or `NotFound`. For convenience, the `found` and `not_found`
methods convert to `Option`, ala `Result`.

Deprecate bsearch and bsearch_elem.
Introduce the cargo run command earlier (squashed)
Sort `Marker types` and add missing language items
Fix handling of ignored arguments in FFI wrappers for rust functions

Fixes #16441.
core: Put stability attributes all over the slice module

Much of this is as discussed[1]. Many things are marked

[1]: https://github.com/rust-lang/meeting-minutes/blob/master/Meeting-API-review-2014-08-06.md
core: Change the argument order on splitn and rsplitn for strs.

This makes it consistent with the same functions for slices,
and allows the search closure to be specified last.

[breaking-change]