const regexp/syntax.DotNL

4 uses

	regexp/syntax (current package)
		parse.go#L62: 	DotNL                           // allow . to match newline
		parse.go#L70: 	MatchNL = ClassNL | DotNL
		parse.go#L967: 			if p.flags&DotNL != 0 {
		parse.go#L1218: 			flags |= DotNL