Update ART Service doc. am: f6886c25e0 am: 5172d3fa31

Original change: https://android-review.googlesource.com/c/platform/art/+/2612931

Change-Id: Ic6e01f93daf3ed8515ed14a67c59ebbfe140361d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>