Fix punctuation in os.execvpe docstring. (GH-15051)

(cherry picked from commit fb6807b)

Co-authored-by: Hasan Ramezani <hasan.r67@gmail.com>

Author: miss-islington

Lib/os.py

@@ -574,7 +574,7 @@ def execvpe(file, args, env):
     """execvpe(file, args, env)
 
     Execute the executable file (which is searched for along $PATH)
-    with argument list args and environment env , replacing the
+    with argument list args and environment env, replacing the
     current process.
     args may be a list or tuple of strings. """
     _execvpe(file, args, env)