Fix Regexp.escape/quote not escaping dollar signs

[timcraft]

Dollar signs should be escaped/quoted:

$ irb
irb(main):001> Regexp.escape '$'
=> "\\$"

[herwinw]

The change looks good. Could you also remove the NATFIXME block in spec/core/regexp/shared/new.rb line 59 (just remove that line and the corresponding end line, and fix the indentation of the current line 60). You've accidentally fixed that bug too ;)

It would be even better if we could include the upstream spec fix too, but that's out of our control.

[timcraft]

Thanks! I mistakenly assumed the build was broken 😆