Update RTFD urls in howto
Update RTFD urls in howto

blueyed/coveragepy,hugovk/coveragepy,nedbat/coveragepy,nedbat/coveragepy,nedbat/coveragepy,blueyed/coveragepy,blueyed/coveragepy,blueyed/coveragepy,hugovk/coveragepy,hugovk/coveragepy,hugovk/coveragepy,nedbat/coveragepy,nedbat/coveragepy,blueyed/coveragepy,hugovk/coveragepy