Update volume behavior documentation.

setDeviceVolumeBehavior doesn't work for any of the absolute volume
behaviors, as they cause AudioService to throw an exception in
setDeviceVolumeBehaviorInternal.

The documentation and runtime checks in AudioManager should be
consistent with this behavior.

Also document compatibility behavior for
DEVICE_VOLUME_BEHAVIOR_ADJUST_ONLY in its definition.

Test: make
Bug: 240663268
Change-Id: I60b7aac0c329dae0e1301362d9803d7586e62602