Support data for Unicode flag on HTML pattern attribute

[valtlai]

Browsers should use the u flag when matching the input value against HTML pattern attribute. (Spec.)

Initial implementations didn’t use the flag, but now at least Chrome, Firefox and Safari Technology Review 53 do.

A test case:

<form>
   <input value="a𝌆b" pattern="a.b" required>
   <button>Test</button>
</form>

Maybe an additional note for https://caniuse.com/#feat=input-pattern would suffice?

[brandung-sjorek]

@Fyrd @valtlai Is there any progress here, as this issue is quite old now? I really like to know how far the adoption of unicode-aware pattern-validation in input-fields has evolved. At least under https://caniuse.com/#feat=input-pattern there is no hint …

Any suggestion?