Fixed a missing . and a missing capital letter. (GH-12170)

(cherry picked from commit 7e9ce4c89e9a34ff84a89831812bc8b42d37ac1f)

Co-authored-by: Jules Lasne (jlasne) <jlasne@student.42.fr>
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index ff91b5d..18be75c 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -959,7 +959,7 @@
 .. data:: CREATE_NO_WINDOW
 
    A :class:`Popen` ``creationflags`` parameter to specify that a new process
-   will not create a window
+   will not create a window.
 
    .. versionadded:: 3.7
 
@@ -1295,7 +1295,7 @@
 
 * :class:`Popen` raises an exception if the execution fails.
 
-* the *capturestderr* argument is replaced with the *stderr* argument.
+* The *capturestderr* argument is replaced with the *stderr* argument.
 
 * ``stdin=PIPE`` and ``stdout=PIPE`` must be specified.