Consider supports the unicode-aware regular expressions in ECMAScript 2015

Is your feature request related to a problem? Please describe.

Not so long ago there was an issue where it was told about RegularExpressionAttribute problems. This eventually led to a clarification in the documentation.

(By the way, it ended up in the wrong section. Therefore, in the documentation, we see it only for a version below aspnetcore-3.0)

But, ECMAScript 2015 does support language elements such as the Unicode category or block elements \p and \P. Now we have to write workarounds. See this SO-answer.

(If I understand correctly, this is now supported by all browsers in this table, except Konq 4.14 and IE 11)