No documentation for `include!` syntax extension

[mbrubeck]

include! does not appear in the docs for the std library, although similar built-in extensions like include_string! do appear there.

[steveklabnik]

Does this macro even exist anymore?

$ git grep "macro_rules\! include"
src/libstd/macros.rs:    macro_rules! include_str { ($file:expr) => ({ /* compiler built-in */ }) }
src/libstd/macros.rs:    macro_rules! include_bytes { ($file:expr) => ({ /* compiler built-in */ }) }

/cc @kmcallister

[kmcallister]

Yes. You are grepping the docs where it's missing and not the actual definition, which is a procedural macro.

[kmcallister]

Related: #22621

[steveklabnik]

ahhhhh