fix comma location in various places (GH-19233)

(cherry picked from commit c49016e67c3255b37599b354a8d7995d40663991)

Co-authored-by: Mathieu Dupuy <deronnax@users.noreply.github.com>
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index de1e717..d364e61 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -17,7 +17,7 @@
 
 :dfn:`Objects` are Python's abstraction for data.  All data in a Python program
 is represented by objects or by relations between objects. (In a sense, and in
-conformance to Von Neumann's model of a "stored program computer," code is also
+conformance to Von Neumann's model of a "stored program computer", code is also
 represented by objects.)
 
 .. index::