go/doc cleanup: remove some unnecessary string conversions
go/doc cleanup: remove some unnecessary string conversions

R=rsc
CC=golang-dev
http://codereview.appspot.com/642041

dsriram/golang,ssrl/go,gnanderson/go,h8liu/golang,nightlyone/golang,dsriram/golang,apparentlymart/golang,gnanderson/go,nightlyone/golang,gnanderson/go,tianon/debian-golang,nightlyone/golang,pombredanne/go-deleteme,tv42/old-go,bdwalton/debian-golang,tianon/debian-golang,tv42/old-go,dsriram/golang,nightlyone/golang,bdwalton/debian-golang,pombredanne/go-deleteme,tv42/old-go,apparentlymart/golang,ssrl/go,apparentlymart/golang,dsriram/golang,pombredanne/go-deleteme,h8liu/golang,bdwalton/debian-golang,tv42/old-go,h8liu/golang,ssrl/go,pombredanne/go-deleteme,tv42/old-go,dsriram/golang,bdwalton/debian-golang,apparentlymart/golang,nightlyone/golang,bdwalton/debian-golang,bdwalton/debian-golang,gnanderson/go,ssrl/go,nightlyone/golang,tianon/debian-golang,gnanderson/go,dsriram/golang,ssrl/go,pombredanne/go-deleteme,ssrl/go,apparentlymart/golang,gnanderson/go,h8liu/golang,h8liu/golang,tianon/debian-golang,bdwalton/debian-golang,tv42/old-go,tianon/debian-golang,bdwalton/debian-golang,tianon/debian-golang,apparentlymart/golang,tv42/old-go,pombredanne/go-deleteme,h8liu/golang,dsriram/golang,pombredanne/go-deleteme,h8liu/golang,ssrl/go,nightlyone/golang,tianon/debian-golang,gnanderson/go,apparentlymart/golang,tianon/debian-golang