Update traits.md

Author: guswynn

src/items/traits.md

@@ -72,7 +72,7 @@ Object safe traits can be the base trait of a [trait object]. A trait is
     * Not have any type parameters (although lifetime parameters are allowed),
       and
     * Be a [method] that does not use `Self` except in the type of the receiver.
-    * otherwise this method is non-dispatchable from a trait object
+    * otherwise this method is non-dispatchable from a trait object.
 * It must not have any associated constants.
 * All [supertraits] must also be object safe.