Update doc for Unity 6

Update the documentation to remove mentions of Unity 2023.3 and replace it by Unity 6

Author: Antoine Lelièvre

Packages/com.unity.render-pipelines.high-definition/Documentation~/Custom-Pass-Injection-Points.md

@@ -24,3 +24,5 @@ Unity triggers the following injection points in a frame, in order from top to b
 | BeforePostProcess         | Color (Pyramid \| Read \| Write), Depth (Read \| Write), Normal and roughness (Read), Motion Vectors (Read) | The available buffers for this injection point contain all geometry in the frame that uses High Dynamic Range (HDR). |
 | AfterPostProcess          | Color (Read \| Write), Depth (Read)                          | The available buffers for this injection point contain the final render of the scene, including post-process effects.<br/><br/>This injection point executes the available buffers after Unity applies any post-processing effects.<br/><br/>If you select this injection point, objects that use the depth buffer display jittering artifacts.<br/><br/>When you select this injection point for a [FullscreenCustom Pass](custom-pass-create-gameobject.md#full-screen-custom-pass), Unity assigns the camera color buffer as the target by default. |
 
+The purple boxes correspond to the injection points above in this diagram representing the pass layout in HDRP:
+![](Images/HDRP-frame-graph-diagram.png)

Packages/com.unity.render-pipelines.high-definition/Documentation~/TableOfContents.md

@@ -16,7 +16,7 @@
   * [High Definition Render Pipeline Wizard](Render-Pipeline-Wizard.md) 
   * [Upgrade guides](upgrade-guides.md)
     * [Material Upgrade](Material-Upgrade.md)
-    * [Upgrade from HDRP 16.x to 17.x](Upgrading-from-2023.2-to-2023.3.md)
+    * [Upgrade from HDRP 16.x to 17.x](Upgrading-from-2023.2-to-unity-6-preview.md)
     * [Upgrade from HDRP 15.x to 16.x](Upgrading-from-2023.1-to-2023.2.md)
     * [Upgrade from HDRP 14.x to 15.x](Upgrading-from-2022.2-to-2023.1.md)
     * [Upgrade from HDRP 13.x to 14.x](Upgrading-from-2022.1-to-2022.2.md)

Packages/com.unity.render-pipelines.high-definition/Documentation~/Upgrading-from-2023.2-to-2023.3.md renamed to Packages/com.unity.render-pipelines.high-definition/Documentation~/Upgrading-from-2023.2-to-unity-6-preview.md

@@ -1,4 +1,4 @@
-# Upgrading HDRP from 2023.2 to 2023.3
+# Upgrading HDRP from 2023.2 to Unity 6 Preview
 
 In the High Definition Render Pipeline (HDRP), some features work differently between major versions. This document helps you upgrade HDRP from 16.x to 17.x.
 

Packages/com.unity.render-pipelines.high-definition/Documentation~/whats-new-17.md

@@ -1,6 +1,6 @@
-# What's new in HDRP version 17 / Unity 2023.3
+# What's new in HDRP version 17 / Unity 6 Preview
 
-This page contains an overview of new features, improvements, and issues resolved in version 17 of the High Definition Render Pipeline (HDRP), embedded in Unity 2023.3.
+This page contains an overview of new features, improvements, and issues resolved in version 17 of the High Definition Render Pipeline (HDRP), embedded in Unity 6 Preview.
 
 ## Added
 
@@ -54,7 +54,7 @@ The HDRP path tracer now offers an option to denoise the volumetric fog effect s
 
 #### GPU Resident Drawer with GPU Occlusion Culling
 
-GPU Resident Drawer Leveraging the power of the [Batch Render Group API](https://docs.unity3d.com/2023.3/Documentation/ScriptReference/Rendering.BatchRendererGroup.html) that allows rigid game objects to be inserted into the BRG leading to significant main thread and render thread performance improvements for rendering. It allows to author your game using game objects and when processed they will be ingested and rendered via a special fast path that handles better instancing. The performance improvements are dependent on the scale of the scenes and the amount of instancing utilize. The more instanceable objects are rendered, the larger the benefits will be. This feature is specifically for standard MeshRenderes. It will not handle skinned mesh renderers, VFX Graphs, particle systems or similar effects renderers.
+GPU Resident Drawer Leveraging the power of the [Batch Render Group API](https://docs.unity3d.com/6000.0/Documentation/ScriptReference/Rendering.BatchRendererGroup.html) that allows rigid game objects to be inserted into the BRG leading to significant main thread and render thread performance improvements for rendering. It allows to author your game using game objects and when processed they will be ingested and rendered via a special fast path that handles better instancing. The performance improvements are dependent on the scale of the scenes and the amount of instancing utilize. The more instanceable objects are rendered, the larger the benefits will be. This feature is specifically for standard MeshRenderes. It will not handle skinned mesh renderers, VFX Graphs, particle systems or similar effects renderers.
 
 The extra GPU Culling functionality built on top of GPU Resident drawer allows for GPU-side culling of instances that do not contribute to the final image. This can help to improve GPU performance in scenes with heavy overdraw, and does not require any additional authoring to try out. With Rendering Debugger integration.