auto merge of #15996 : nham/rust/smallintmap_not_hashmap, r=sanxiyn

SmallIntMap doesn't involve hashing?

src/libcollections/smallintmap.rs

@@ -263,7 +263,7 @@ pub fn mut_iter<'r>(&'r mut self) -> MutEntries<'r, V> {
         }
     }
 
-    /// Empties the hash map, moving all values into the specified closure.
+    /// Empties the map, moving all values into the specified closure.
     ///
     /// # Example
     ///