peg.parsers-docs: fix some typos
peg.parsers-docs: fix some typos

mrjbq7/factor,factor/factor,tgunr/factor,factor/factor,mrjbq7/factor,mrjbq7/factor,tgunr/factor,mrjbq7/factor,factor/factor,tgunr/factor,tgunr/factor,mrjbq7/factor,mrjbq7/factor,factor/factor,factor/factor,factor/factor,tgunr/factor,tgunr/factor