Bump hypothesis-python version to 6.127.9 and update changelog

[skip ci]

hypothesis-python/docs/changes.rst

@@ -18,6 +18,29 @@ Hypothesis 6.x
 
     .. include:: ../RELEASE.rst
 
+.. _v6.127.9:
+
+--------------------
+6.127.9 - 2025-03-06
+--------------------
+
+We now provide a better string representation for :func:`~hypothesis.strategies.one_of` strategies, by flattening consecutive ``|`` combinations. For instance:
+
+.. code-block:: pycon
+
+    >>> st.integers() | st.text() | st.booleans()
+    # previously: one_of(one_of(integers(), text()), booleans())
+    one_of(integers(), text(), booleans())
+
+Explicit calls to :func:`~hypothesis.strategies.one_of` remain unflattened, in order to make tracking down complicated :func:`~hypothesis.strategies.one_of` constructions easier:
+
+.. code-block:: pycon
+
+    >>> st.one_of(st.integers(), st.one_of(st.text(), st.booleans()))
+    one_of(integers(), one_of(text(), booleans()))
+
+We print ``one_of`` in reprs (rather than ``integers() | text() | ...``) for consistency with reprs containing ``.filter`` or ``.map`` calls, which uses the full ``one_of`` to avoid ambiguity.
+
 .. _v6.127.8:
 
 --------------------

hypothesis-python/src/hypothesis/version.py

@@ -8,5 +8,5 @@
 # v. 2.0. If a copy of the MPL was not distributed with this file, You can
 # obtain one at https://mozilla.org/MPL/2.0/.
 
-__version_info__ = (6, 127, 8)
+__version_info__ = (6, 127, 9)
 __version__ = ".".join(map(str, __version_info__))