Update OpenXR Settings page for 4.6

Author: skyace65

tutorials/xr/img/openxr_eye_gaze_interaction.webp

@@ -236,6 +236,18 @@ Debug Message Types
 
 This allows you to choose which debug messages are logged.
 
+Frame Synthesis
+~~~~~~~~~~~~~~~
+
+When enabled, provided its supported by the XR runtime, a lower resolution motion
+vector buffer and depth buffer is rendered and provided to the XR runtime. The XR
+runtime can now inject reprojection frames and compensate for lower framerates.
+
+It currently has the following limitations:
+
+- Does NOT work on the Forward+ renderer.
+- Only works with stereo rendering.
+
 Hand Tracking
 ~~~~~~~~~~~~~
 
@@ -278,6 +290,13 @@ the user is holding a controller.
 If only a hand interaction profile is supplied any runtime should use hand
 interaction even if a controller is being held.
 
+Spatial Entity
+~~~~~~~~~~~~~~
+
+This extension and its settings are used for obtaining and interacting with
+information about the users real world environment. You can find more detailed
+information on how it works on the spatial entities page :ref:`here <doc_openxr_spatial_entities>`.
+
 Eye Gaze Interaction
 ~~~~~~~~~~~~~~~~~~~~