Improve documentation on Vibrator.vibrate.
Improve documentation on Vibrator.vibrate.

Bug: 3135537
Change-Id: I961e32990d754dc6b5f86ffea8515685f8ade40f

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base