Merge "Update javadoc for Notification#setOngoing" into udc-dev am: 11d35a35 am: 477de35a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22100024



Change-Id: I438af85d5ef09c0721ed8b1596c8dd103e7bcbc8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>