Refs #27236 -- Reverted AlterIndexTogether deprecation.

This partly reverts a6385b382e.

docs/internals/deprecation.txt

@@ -19,9 +19,6 @@ details on these changes.
 
 * The model's ``Meta.index_together`` option will be removed.
 
-* The ``AlterIndexTogether`` migration operation will be removed. A stub
-  operation will remain for compatibility with historical migrations.
-
 * The ``length_is`` template filter will be removed.
 
 * The ``django.contrib.auth.hashers.SHA1PasswordHasher``,

docs/ref/checks.txt

@@ -397,12 +397,6 @@ Models
 * **models.W045**: Check constraint ``<constraint>`` contains ``RawSQL()``
   expression and won't be validated during the model ``full_clean()``.
 
-Migrations
-----------
-
-* **migrations.W001**: ``AlterIndexTogether`` is deprecated. Support for it
-  (except in historical migrations) will be removed in Django 5.1.
-
 Security
 --------
 

docs/ref/migration-operations.txt

@@ -106,13 +106,6 @@ Changes the model's set of custom indexes (the
 :attr:`~django.db.models.Options.index_together` option on the ``Meta``
 subclass).
 
-.. deprecated:: 4.2
-
-    ``AlterIndexTogether`` is deprecated in favor of
-    :class:`~django.db.migrations.operations.AddIndex`,
-    :class:`~django.db.migrations.operations.RemoveIndex`, and
-    :class:`~django.db.migrations.operations.RenameIndex` operations.
-
 ``AlterOrderWithRespectTo``
 ---------------------------
 

docs/releases/4.2.txt

@@ -319,8 +319,6 @@ Miscellaneous
   <https://docs.python.org/3/library/secrets.html#recipes-and-best-practices>`_
   for using Python's :py:mod:`secrets` module to generate passwords.
 
-* The ``AlterIndexTogether`` migration operation is deprecated.
-
 * The ``length_is`` template filter is deprecated in favor of :tfilter:`length`
   and the ``==`` operator within an :ttag:`{% if %}<if>` tag. For example