Merge "Clarify documentation for the dimming stage." into tm-dev am: 581b7b11bd

Original change: https://googleplex-android-review.googlesource.com/c/platform/hardware/interfaces/+/17263930

Change-Id: Ib6e8d87b9fd563d91a1c43e47e54c47568078e90
Signed-off-by: Automerger Merge Worker