bpo-33185: Improve wording and markup (GH-6477)

Adds some working and markup fixes that I missed
in the initial commit for this issue.

(Follow-up to GH-6419)
diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index 735ad9d..e7a1655 100644
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -2643,7 +2643,7 @@
 
 # Note: the tests only cover _get_revised_path, not _adjust_cli_path itself
 def _adjust_cli_sys_path():
-    """Ensures current directory is on sys.path, and __main__ directory is not
+    """Ensures current directory is on sys.path, and __main__ directory is not.
 
     Exception: __main__ dir is left alone if it's also pydoc's directory.
     """