Add missing chars to CharcterClass escaped chars

[mingodad]

Add missing - escaped char here

cpp-peglib/peglib.h

Line 3442 in 527422a

cho(seq(chr('\\'), cls("fnrtv'\"[]\\^")),

cho(seq(chr('\\'), cls("fnrtv'\"[]\\^-")),

[yhirose]

@mingodad thanks!