minesweeper: adding docs for middle-click.
minesweeper: adding docs for middle-click.

tgunr/factor,factor/factor,AlexIljin/factor,tgunr/factor,mrjbq7/factor,mrjbq7/factor,bpollack/factor,bpollack/factor,bpollack/factor,tgunr/factor,AlexIljin/factor,tgunr/factor,bpollack/factor,factor/factor,AlexIljin/factor,bpollack/factor,mrjbq7/factor,tgunr/factor,AlexIljin/factor,factor/factor,mrjbq7/factor,mrjbq7/factor,mrjbq7/factor,AlexIljin/factor,bpollack/factor,AlexIljin/factor,factor/factor,bpollack/factor,AlexIljin/factor,factor/factor,tgunr/factor,factor/factor