regexp.minimize: use sort-pair instead of natural-sort.
regexp.minimize: use sort-pair instead of natural-sort.

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