Merge #268

268: Expose proc macro docs via the main crate r=nikomatsakis a=1tgr

Improve visibility by placing the `database` and `query_group` proc macros at the bottom of the main docs page, instead of manually browsing to the docs for the `salsa-macros` crate.

Co-authored-by: Tim Robinson <tim.g.robinson@gmail.com>

src/lib.rs

@@ -605,5 +605,4 @@ impl std::error::Error for Cancelled {}
 #[macro_use]
 extern crate salsa_macros;
 use plumbing::HasQueryGroup;
-#[doc(hidden)]
 pub use salsa_macros::*;