Adds temporary regression test; this ideally should work as-is (rust-lang#41430)

Closes rust-lang#41211

Fix rust-lang#33884

[unstable, deprecated since 1.16.0]

[unstable, deprecated since 1.13.0]

[unstable, deprecated since 1.12.0]

[unstable, deprecated since 1.15.0]

[unstable, deprecated since 1.15.0]

[unstable, deprecated since 1.12.0]

[unstable, deprecated since 1.15.0]

[unstable, deprecated since 1.11.0]

[unstable, deprecated since 1.11.0]

…komatsakis,eddyb

Ref suggestion

…ovement, r=steveklabnik

Fix line display for hoedown

Fixes rust-lang#41401.

r? @rust-lang/docs

Don't panic if an attribute macro fails to resolve at crate root

Adds temporary regression test; this ideally should work as-is (rust-lang#41430)

Closes rust-lang#41211

r? @jseyfried

Add test for issue 33884

Fix rust-lang#33884.

r=nikomatsakis

… r=alexcrichton

Remove items that are unstable and deprecated

This removes unstable items that have been deprecated for more than one cycle.

- Since 1.16.0, `#![feature(enumset)]`
    - All of `mod collections::enum_set`
- Since 1.15.0, `#![feature(borrow_state)]`
    - `cell::BorrowState`
    - `RefCell::borrow_state()`
- Since 1.15.0, `#![feature(is_unique)]`
    - `Rc::is_unique()` (made private like `Arc::is_unique()`)
- Since 1.15.0, `#![feature(rc_would_unwrap)]`
    - `Rc::would_wrap()`
- Since 1.13.0, `#![feature(binary_heap_extras)]`
    - `BinaryHeap::push_pop()`
    - `BinaryHeap::replace()`
- Since 1.12.0, `#![feature(as_unsafe_cell)]`
    - `Cell::as_unsafe_cell()`
    - `RefCell::as_unsafe_cell()`
- Since 1.12.0, `#![feature(map_entry_recover_keys)]`
    - `btree_map::OccupiedEntry::remove_pair()`
    - `hash_map::OccupiedEntry::remove_pair()`
- Since 1.11.0, `#![feature(float_extras)]`
    - `Float::nan()`
    - `Float::infinity()`
    - `Float::neg_infinity()`
    - `Float::neg_zero()`
    - `Float::zero()`
    - `Float::one()`
    - `Float::integer_decode()`
    - `f32::integer_decode()`
    - `f32::ldexp()`
    - `f32::frexp()`
    - `f32::next_after()`
    - `f64::integer_decode()`
    - `f64::ldexp()`
    - `f64::frexp()`
    - `f64::next_after()`
- Since 1.11.0, `#![feature(zero_one)]`
    - `num::Zero`
    - `num::One`