fix #21076: turn signal module constants into enums
diff --git a/Doc/library/signal.rst b/Doc/library/signal.rst
index 84e2836..a97ce66 100644
--- a/Doc/library/signal.rst
+++ b/Doc/library/signal.rst
@@ -65,6 +65,16 @@
Module contents
---------------
+.. versionchanged:: 3.5
+ signal (SIG*), handler (:const:`SIG_DFL`, :const:`SIG_IGN`) and sigmask
+ (:const:`SIG_BLOCK`, :const:`SIG_UNBLOCK`, :const:`SIG_SETMASK`)
+ related constants listed below were turned into
+ :class:`enums <enum.IntEnum>`.
+ :func:`getsignal`, :func:`pthread_sigmask`, :func:`sigpending` and
+ :func:`sigwait` functions return human-readable
+ :class:`enums <enum.IntEnum>`.
+
+
The variables defined in the :mod:`signal` module are: