xml.writer: fix some docs.
xml.writer: fix some docs.

mrjbq7/factor,bjourne/factor,tgunr/factor,tgunr/factor,mrjbq7/factor,slavapestov/factor,AlexIljin/factor,AlexIljin/factor,factor/factor,dch/factor,nicolas-p/factor,sarvex/factor-lang,dch/factor,sarvex/factor-lang,tgunr/factor,factor/factor,AlexIljin/factor,nicolas-p/factor,AlexIljin/factor,mrjbq7/factor,factor/factor,nicolas-p/factor,mrjbq7/factor,nicolas-p/factor,dch/factor,slavapestov/factor,bpollack/factor,slavapestov/factor,dch/factor,bpollack/factor,nicolas-p/factor,mrjbq7/factor,slavapestov/factor,AlexIljin/factor,mrjbq7/factor,bpollack/factor,bpollack/factor,sarvex/factor-lang,AlexIljin/factor,dch/factor,bpollack/factor,tgunr/factor,bjourne/factor,bpollack/factor,sarvex/factor-lang,bjourne/factor,slavapestov/factor,sarvex/factor-lang,factor/factor,tgunr/factor,dch/factor,sarvex/factor-lang,slavapestov/factor,sarvex/factor-lang,bjourne/factor,factor/factor,AlexIljin/factor,slavapestov/factor,bjourne/factor,tgunr/factor,bjourne/factor,factor/factor,nicolas-p/factor,nicolas-p/factor,bpollack/factor,bjourne/factor