bpo-38096:  Complete the "structseq" and "named tuple" cleanup (GH-16010) (GH-16062)

(cherry picked from commit 4210ad5ebd5769f585035e022876e161cd0e9a3e)

Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>
diff --git a/Doc/glossary.rst b/Doc/glossary.rst
index 84d0fca..e601e8b 100644
--- a/Doc/glossary.rst
+++ b/Doc/glossary.rst
@@ -757,7 +757,7 @@
       Some named tuples are built-in types (such as the above examples).
       Alternatively, a named tuple can be created from a regular class
       definition that inherits from :class:`tuple` and that defines named
-      fields.  Such as class can be written by hand or it can be created with
+      fields.  Such a class can be written by hand or it can be created with
       the factory function :func:`collections.namedtuple`.  The latter
       technique also adds some extra methods that may not be found in
       hand-written or built-in named tuples.