Added example for RegExp.prototype.hasIndices

[SebastianZ]

This adds an interactive example for the newly introduced RegExp.prototype.hasIndices property.

This is in preparation of adding the related content.

Sebastian

[welcome]

💖 Thanks for opening this pull request! 💖
Here is a list of things that will help get it across the finish line:

• If this is a new or updated CSS interactive example, please ensure that you followed the CSS styleguide - If this is a new or updated JavaScript interactive example, please ensure that you followed the JavaScript styleguide - If your changes affects any of the steps in our contribution docs, please also make the relevant changes there.

[chrisdavidmills]

Thanks @SebastianZ ! This looks fine. The DotAll example works fine, and the HasIndices examples works fine in newest Firefox 88 build and newest Chrome Canary.

The only problem we've got here is that the ESLint CI build is failing, I'm guessing because the version of ESLint we are using doesn't know about hasIndices yet. @schalkneethling can this be updated easily?

[escattone]

I updated eslint to the latest version 7.23.0, but it still doesn't recognize the d flag as it should. I'm going to merge this for now, and we can keep looking into resolving the eslint issue.

[welcome]

Congrats on merging your first pull request! 🎉🎉🎉

[SebastianZ]

Muchas gracias, Ryan, for merging my PR! 😃

I assume, the d flag is just too new and therefore not implemented in Node.js yet.

Sebastian