gh-141004: Document `Py_hexdigits` (GH-141059)

Co-authored-by: Victor Stinner <vstinner@python.org>

diff --git a/Doc/c-api/codec.rst b/Doc/c-api/codec.rst
index 08a99245ad6528f139dd6f0107859ce917a8eb36..35ee048bd5fa9f575b02a58c5e830e329b245a62 100644 (file)
--- a/Doc/c-api/codec.rst
+++ b/Doc/c-api/codec.rst
@@ -129,3 +129,13 @@ Registry API for Unicode encoding error handlers
    Replace the unicode encode error with ``\N{...}`` escapes.
 
    .. versionadded:: 3.5
+
+
+Codec utility variables
+-----------------------
+
+.. c:var:: const char *Py_hexdigits
+
+   A string constant containing the lowercase hexadecimal digits: ``"0123456789abcdef"``.
+
+   .. versionadded:: 3.3