feat: add remove option field to playground

[screensaversclub]

• Create new RegExp from user input
• "global" and "ignore case" flags are exposed as checkboxes to user
• Tested with simple regex like /[aeiou]/gi (remove vowels) or /(?<= )((a)|(an)|(the))(?= )/gi (remove a/an/the with both positive and negative lookahead for space character)

[Trott]

Totally optional suggestion that you can feel free to ignore (or save for another PR), but the remove option is sort of an advanced option that very few (no?) users actually need, and that gets misunderstood/misused a lot, so it might not be a terrible idea to hide it in an element that needs to be expanded, maybe with something like this?:

<details>
<summary>Advanced options</summary>
Remove: <input type="text">
</details>

[screensaversclub]

Happy to do so as I think you have a better idea how people tend to use the package. I'll push a commit with that.

Do you think the charmap and multicharmap options would be folded into this advanced disclosure as well?

[Trott]

Do you think the charmap and multicharmap options would be folded into this advanced disclosure as well?

I'd leave those out entirely. I can't even imagine a reliable way to implement them that isn't a UX nightmare.

[screensaversclub]

@Trott circling back to this, do you think there's anything else you'd like to rethink about this PR here? (Not sure if it's pending my action. ) Thanks!

[Trott]

@screensaversclub Thanks for your patience. This looks good and I'll land it now.