Add Nutilz Regex Tester to Regex

[Buddy69-Lanka]

Adds Nutilz Regex Tester to the Regex section.

• In-browser regex tester and debugger with real-time match highlighting, regex syntax breakdown, and group extraction
• 100% client-side — runs entirely in the browser
• Free, no signup required, no usage limits

Placed alphabetically between ExtendsClass and Regexr. Thanks for maintaining this list!

[github-actions]

Hey Buddy69-Lanka! Thanks for your submission! 🚀

To keep awesome-devtools instantly accessible for everyone, all tools must be:

• Browser-based — no downloads or native app installs
• Direct link — goes straight to the tool (not a multi-tool landing page)
• 100% free — no signups, trials, paywalls, or usage limits

Please make sure your PR meets these criteria. It may take some time for your submission to be reviewed — you can occasionally comment with a "bump" to bring more attention to it.

Thanks for contributing! 🙌