Add RegexpNode regopt predicates

[owst]

As suggested by @bbatsov here:
rubocop/rubocop#8073 (comment)

[marcandre]

Looks great!
Would you also add the "o" option please?

[owst]

Oops - accidental omission, thanks @marcandre !

I've never used the o option before, and I struggled to find an example where it causes a change in behaviour. I finally came up with:

[1] pry(main)> Array.new(3) { |i| /#{i}/ }
=> [/0/, /1/, /2/]
[2] pry(main)> Array.new(3) { |i| /#{i}/o }
=> [/0/, /0/, /0/]

even then, I'm not sure when this would be useful!

The Perl docs say:

o - pretend to optimize your code, but actually introduce bugs

😄

[bbatsov]

Thanks!

[marcandre]

Oh, that actually breaks RuboCop. Probably a naming conflict with multiline?. I'm reopening #5

[owst]

Good catch @marcandre and 👍 for running RuboCop specs too