Changes to Cooperative Threading between r0 and r1

'''Cooperative Threading (sometimes called "[fibers]")''' --> '''Cooperative Threading'''

Threading model where each thread must ''explicitly'' give up control of the process or CPU to allow other threads to run. --> This threading model is sometimes called "[fibers]". It is the threading model where each thread must ''explicitly'' give up control of the process or CPU to allow other threads to run.

Legend

     Only in r0
     Only in r1
     -->      Modified slightly between r0 and r1