Merge "Updates the doc for FEATURE_WINDOW_MAGNIFICATION" into tm-dev am: 70a4c7685c am: eadf306754

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17394606

Change-Id: Ifa2a3b3263e423ea921adc551fc38904150604b8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>