Docs: Grammar fix (it's -> its) am: 444b464c am: 4db9d2a8 am: 02e0eb2a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23829884



Change-Id: I2e7246e17eaef8f987006fa164d28b7f33d91e41
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>