[3.11] Add a mention of PYTHONBREAKPOINT to breakpoint() docs (GH-104430) (#104447)

Add a mention of PYTHONBREAKPOINT to breakpoint() docs (GH-104430)
(cherry picked from commit 1be80ed107deb15b926f2794b8e6a7a527b8b84c)

Co-authored-by: Ned Batchelder <ned@nedbatchelder.com>

diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index f3dc02f03db0e96e54bb1fb266b1c52bd571f95b..d1ce1520fdbb5db5be5477db4d9d344c892530e4 100644 (file)
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -168,6 +168,13 @@ are always available.  They are listed here in alphabetical order.
    If :func:`sys.breakpointhook` is not accessible, this function will
    raise :exc:`RuntimeError`.
 
+   By default, the behavior of :func:`breakpoint` can be changed with
+   the :envvar:`PYTHONBREAKPOINT` environment variable.
+   See :func:`sys.breakpointhook` for usage details.
+
+   Note that this is not guaranteed if :func:`sys.breakpointhook`
+   has been replaced.
+
    .. audit-event:: builtins.breakpoint breakpointhook breakpoint
 
    .. versionadded:: 3.7