Issue #13685 - Update argparse help message for % sign usage.
diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 186e12d..d64f8a2 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -1082,6 +1082,9 @@
optional arguments:
-h, --help show this help message and exit
+As the help string supports %-formatting, if you want a literal ``%`` to appear
+in the help string, you must escape it as ``%%``.
+
:mod:`argparse` supports silencing the help entry for certain options, by
setting the ``help`` value to ``argparse.SUPPRESS``::