grammatical fix

Author: adqm

peps/pep-0798.rst

@@ -926,7 +926,7 @@ One of the common questions about the semantics outlined above had to do with
 the difference between using ``yield from`` when unpacking inside of a
 generator expression, versus using an explicit loop.  Because this is a
 fairly-advanced feature of generators, this appendix attempts to summarize some
-of the key differences between generators that use ``yield from`` versus those
+of the key differences between generators that use ``yield from`` and those
 that use explicit loops.
 
 Basic Behavior