doc: credit Wintreist and document the preserved composition order

The regression test for pytest-dev#14329 is Wintreist's, taken verbatim from
pytest-dev#14332; carry the attribution and add them to AUTHORS.

Also spell out in the changelog what does *not* change: `own_markers`
keeps its base-first order, and so do the consumers that compose markers
rather than look one up. `usefixtures` requests its fixtures in the same
order as before, and an inherited class level `parametrize` composes the
same test IDs as before -- no pinned ID selection and no `--last-failed`
cache is invalidated by this fix.

Co-authored-by: Wintreist <49996562+Wintreist@users.noreply.github.com>
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: 3 people

AUTHORS

@@ -526,6 +526,7 @@ Wil Cooley
 Will Riley
 William Lee
 Wim Glenn
+Wintreist
 Wouter van Ackooy
 Xixi Zhao
 Xuan Luong

changelog/14329.bugfix.rst

@@ -2,8 +2,8 @@
 now walk the class MRO closest-first, so a marker on a subclass takes precedence over the
 same marker on one of its base classes.
 
-``own_markers`` keeps its previous (base class first) order.
-
-As a consequence, :ref:`usefixtures <usefixtures>` markers are now iterated in reverse, which
-keeps base class fixtures being requested before subclass ones, and additionally makes stacked
-``usefixtures`` markers on a single node request their fixtures in source order.
+``own_markers`` keeps its previous (base class first) order, and so do the consumers that
+compose markers rather than look one up: :ref:`usefixtures <usefixtures>` fixtures are still
+requested in the same order as before, and inherited class level
+:ref:`parametrize <pytest.mark.parametrize ref>` markers still compose their test IDs the
+same way.