Verify: Display the regex

[sinus-x]

We can use https://jex.im/regulex to generate regex visualisations (for example, https://jex.im/regulex/#!cmd=export&flags=&re=[a-z]{5}[a-z0-9]{2}). We could then download the image (it would probably require HTML parsing, because it's a <canvas>) and send it with the error message.
OR we can just link it, in which case we could use https://regexper.com/#x[a-z]{5}[a-z0-9]{2} which has simpler UI.