Revert the changelog to unreleased state, the 3.4.0 release will be delayed due to internal issues with CI.

PiperOrigin-RevId: 840362346
Change-Id: Ic0fb5d6d521c5abc1b98d5242416eac6c7d056c8

doc/changelog.rst

@@ -2,8 +2,9 @@
 Changelog
 =========
 
-Version 3.4.0 (December 1, 2025)
+
---------------------------------
+Upcoming version (not yet released)
+-----------------------------------
 
 General
 ^^^^^^^
@@ -12,20 +13,20 @@ General
    :align: right
    :width: 35%
 
-1. Introduced a major new feature: :ref:`sleeping islands<Sleeping>`. Preliminary release for early testing, see
+- Introduced a major new feature: :ref:`sleeping islands<Sleeping>`. Preliminary release for early testing, see
-   documentation for details.
+  documentation for details.
-2. Added "quadratic" option to :ref:`flexcomp/dof<body-flexcomp-dof>`. This type of fast :ref:`deformable<CDeformable>`
+- Added "quadratic" option to :ref:`flexcomp/dof<body-flexcomp-dof>`. This type of fast :ref:`deformable<CDeformable>`
-   flex object is similar to the "trilinear" option, but it includes curved deformations.
+  flex object is similar to the "trilinear" option, but it includes curved deformations.
-3. Raise an error if there are name collisions also during parsing.
+- Raise an error if there are name collisions also during parsing.
-4. Increase Windows stack size to 16MB to enable models with deep nested body hierarchies.
+- Increase Windows stack size to 16MB to enable models with deep nested body hierarchies.
-5. Added a new pipeline component function :ref:`mj_fwdKinematics` that combines all kinematics-like sub-components.
+- Added a new pipeline component function :ref:`mj_fwdKinematics` that combines all kinematics-like sub-components.
-   Relatedly, added a clarifying table at the top of the :ref:`Simulation Pipeline<Pipeline>` chapter.
+  Relatedly, added a clarifying table at the top of the :ref:`Simulation Pipeline<Pipeline>` chapter.
-6. Added a new :ref:`mj_extractState` function that allows a subset of a state that was previously returned by
+- Added a new :ref:`mj_extractState` function that allows a subset of a state that was previously returned by
-   :ref:`mj_getState` to be extracted without having to be written back into ``mjData`` first.
+  :ref:`mj_getState` to be extracted without having to be written back into ``mjData`` first.
-7. Added a new :ref:`mj_copyState` function that copies state components from one ``mjData`` to another.
+- Added a new :ref:`mj_copyState` function that copies state components from one ``mjData`` to another.
-8. Tendon paths can now be queried from Python via ``MjsTendon.path``, the returned object
+- Tendon paths can now be queried from Python via ``MjsTendon.path``, the returned object
-   is iterable and indexing it will give the ``MjsWrap`` at the given index in the path.
+  is iterable and indexing it will give the ``MjsWrap`` at the given index in the path.
-9. ``MjsWrap`` now exposes:
+- ``MjsWrap`` now exposes:
 
    - ``type -> mujoco.mjtWrap``
    - ``target -> MjsSite|MjsJoint|MjsGeom|None``
@@ -33,15 +34,15 @@ General
    - ``coef -> real``
    - ``divisor -> real``
 
-10. Non-breaking ABI changes:
+- Non-breaking ABI changes:
 
-    - :ref:`mjtSize` is now defined as ``int64_t`` rather than ``uint64_t`` to avoid future type-promotion bugs.
+  - :ref:`mjtSize` is now defined as ``int64_t`` rather than ``uint64_t`` to avoid future type-promotion bugs.
-    - :ref:`mj_sizeModel` now returns an :ref:`mjtSize` rather than an ``int``.
+  - :ref:`mj_sizeModel` now returns an :ref:`mjtSize` rather than an ``int``.
 
 MJX
 ^^^
 
-11. ``warp-lang`` optional dependency is updated to 1.10.0. ``pmap`` now works with MuJoCo Warp from MJX.
+- ``warp-lang`` optional dependency is updated to 1.10.0. ``pmap`` now works with MuJoCo Warp from MJX.
 
 .. admonition:: Breaking ABI changes
    :class: attention
@@ -54,7 +55,7 @@ MJX
 Bug fixes
 ^^^^^^^^^
 
-12. Fixed a bug in the box-box distance computation. Reported by :github:user:`nvtw`.
+- Fixed a bug in the box-box distance computation. Reported by :github:user:`nvtw`.
 
 Version 3.3.7 (October 13, 2025)
 --------------------------------