Task list for VK_KHR_video_encode_feedback2 release

This extension adds support for additional video encode feedback and per-picture partition encode feedback.

The task list for the VK_KHR_video_encode_feedback2 release is:

Title of issue: Task list for release

The task list for the release is:

- [x] Vulkan Specification: [VK_KHR_video_encode_feedback2](https://docs.vulkan.org/refpages/latest/refpages/source/VK_KHR_video_encode_feedback2.html)
- [ ] Conformance tests released: coming soon
- [ ] SDK released: coming soon

- [x] Validation layer: https://github.com/KhronosGroup/Vulkan-ValidationLayers/pull/12429

As each component is made public, the task will be checked off. When all tasks have been completed this issue will be closed and the extension will be fully released.