Reference RFC 199 for ownership variants, mention into_iter

Author: aturon

style/naming/ownership.md

@@ -1,4 +1,6 @@
-% Ownership variants
+% Ownership variants [RFC #199]
+
+> The guidelines below were approved by [RFC #199](https://github.com/rust-lang/rfcs/pull/199).
 
 Functions often come in multiple variants: immutably borrowed, mutably
 borrowed, and owned.
@@ -22,6 +24,11 @@ If `foo` uses/produces owned data by default, use:
 
 #### Exceptions
 
+In the case of iterators, the moving variant can also be understood as
+an `into` conversion, `into_iter`, and `for x in v.into_iter()` reads
+arguably better than `for x in v.iter_move()`, so the convention is
+`into_iter`.
+
 For mutably borrowed variants, if the `mut` qualifier is part of a
 type name (e.g. `as_mut_slice`), it should appear as it would appear
 in the type.