docs: Fix phrasing for BroadcastReceiver.PendingResult am: a3b64f08 am: 02cab8b8 am: a267ce46 am: bf857052

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23879894



Change-Id: I532f2c909cae194980e0980e923795196bf0e3ca
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>