#[macro use] should suggest #[macro_use] and similar

[Havvy]

I swapped an underscore for a space while typing out the attribute. It'd be nice if the error message said that instead of the mess it shows here:

error: expected identifier, found reserved keyword `macro`
 --> src/bin/factoid.rs:3:3
  |
3 | #[macro use]
  |   ^^^^^ expected identifier, found reserved keyword

error: cannot find macro `setup_panic!` in this scope
  --> src/bin/factoid.rs:13:5
   |
13 |     setup_panic!(Metadata {
   |     ^^^^^^^^^^^

error[E0658]: The attribute `r#macro` is currently unknown to the compiler and may have meaning added to it in the future (see issue #29642)
 --> src/bin/factoid.rs:3:1
  |
3 | #[macro use]
  | ^^^^^^^^^^^^

error: expected one of `(` or `=`, found `use`
 --> src/bin/factoid.rs:3:9
  |
1 | extern crate clap;
  | - expected one of `(` or `=` here
2 | extern crate exitcode;
3 | #[macro use]
  |         ^^^ unexpected token

This should also happen for all the other macros with underscores in them:

• crate_name
• crate_type
• no_builtins
• no_main
• no_start
• no_std
• recursion_limit
• windows_subsystem
• no_implicit_prelude
• link_args
• linked_from
• link_name
• macro_use
• macro_reexport
• macro_export
• no_link
• export_name
• no_mangle
• link_section
• cfg_attr
• must_use