Merge "Update shell_and_utilities docs for U." am: 799550dd

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2464831



Change-Id: I7c2ac6e2a4a82d86e3aebe01096a564530bcdae3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>