Fixed #12916 -- Added a missing versionadded marker for the m2m_changed signal.…

Fixed #12916 -- Added a missing versionadded marker for the m2m_changed signal. Thanks to timo for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12514 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/ref/signals.txt

@@ -176,6 +176,8 @@ m2m_changed
 .. data:: django.db.models.signals.m2m_changed
    :module:
 
+.. versionadded:: 1.2
+
 Sent when a :class:`ManyToManyField` is changed on a model instance.
 Strictly speaking, this is not a model signal since it is sent by the
 :class:`ManyToManyField`, but since it complements the