The third and final doc-string sweep by Ka-Ping Yee.

The attached patches update the standard library so that all modules
have docstrings beginning with one-line summaries.

A new docstring was added to formatter.  The docstring for os.py
was updated to mention nt, os2, ce in addition to posix, dos, mac.
diff --git a/Lib/symbol.py b/Lib/symbol.py
index 73b33e0..8278b22 100755
--- a/Lib/symbol.py
+++ b/Lib/symbol.py
@@ -1,7 +1,7 @@
 #! /usr/bin/env python
-#
-#  Non-terminal symbols of Python grammar (from "graminit.h")
-#
+
+"""Non-terminal symbols of Python grammar (from "graminit.h")."""
+
 #  This file is automatically generated; please don't muck it up!
 #
 #  To update the symbols in this file, 'cd' to the top directory of