[PR #7043/bee613d0 backport][3.10] Add clarification about `GracefulE…

…xit` when using `handle_signals=True` (#9122)

**This is a backport of PR #7043 as merged into master
(bee613d).**

Co-authored-by: Daste <stefankar1000@gmail.com>

CHANGES/4414.doc

@@ -0,0 +1 @@
+Clarified that ``GracefulExit`` needs to be handled in ``AppRunner`` and ``ServerRunner`` when using ``handle_signals=True``. -- by :user:`Daste745`

docs/web_reference.rst

@@ -2734,7 +2734,8 @@ application on specific TCP or Unix socket, e.g.::
    :param bool handle_signals: add signal handlers for
                                :data:`signal.SIGINT` and
                                :data:`signal.SIGTERM` (``False`` by
-                               default).
+                               default). These handlers will raise
+                               :exc:`GracefulExit`.
 
    :param kwargs: named parameters to pass into
                   web protocol.
@@ -2807,7 +2808,8 @@ application on specific TCP or Unix socket, e.g.::
    :param bool handle_signals: add signal handlers for
                                :data:`signal.SIGINT` and
                                :data:`signal.SIGTERM` (``False`` by
-                               default).
+                               default). These handlers will raise
+                               :exc:`GracefulExit`.
 
    :param kwargs: named parameters to pass into
                   web protocol.
@@ -2938,6 +2940,16 @@ application on specific TCP or Unix socket, e.g.::
 
                        ``128`` by default.
 
+.. exception:: GracefulExit
+
+   Raised by signal handlers for :data:`signal.SIGINT` and :data:`signal.SIGTERM`
+   defined in :class:`AppRunner` and :class:`ServerRunner`
+   when ``handle_signals`` is set to ``True``.
+
+   Inherited from :exc:`SystemExit`,
+   which exits with error code ``1`` if not handled.
+
+
 Utilities
 ---------