Canonicalize special cases of map (5.2) move to own module (2) only import used items

Author: phimuemue

src/adaptors/mod.rs

@@ -8,7 +8,9 @@ mod coalesce;
 mod map;
 mod multi_product;
 pub use self::coalesce::*;
-pub use self::map::*;
+pub use self::map::{map_into, map_ok, MapInto, MapOk};
+#[allow(deprecated)]
+pub use self::map::MapResults;
 #[cfg(feature = "use_std")]
 pub use self::multi_product::*;