fix comma location in various places (GH-19233)

diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index e91e855..1c27063 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::
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
index 3fcc5e1..16542cd 100644
--- a/Doc/reference/expressions.rst
+++ b/Doc/reference/expressions.rst
@@ -28,7 +28,7 @@
 .. index:: pair: arithmetic; conversion
 
 When a description of an arithmetic operator below uses the phrase "the numeric
-arguments are converted to a common type," this means that the operator
+arguments are converted to a common type", this means that the operator
 implementation for built-in types works as follows:
 
 * If either argument is a complex number, the other is converted to complex;