Add attribute wildcards, e.g., for HTML5 data-*

[beargiles]

Discussed in #2224

^{Originally posted by beargiles November 15, 2024}
Applications have defined custom attributes for a long time, e.g., aria-*, and with HTML5 (iirc) there's now an official standard to recognize data-* as a valid attribute. For example aria-xyz should become data-aria-xyz.

It's not practical to add all possible attributes - it's an undefined list - and we don't want to specify :all since that will include everything. The best solution appears to be adding an optional list of java.text.Pattern objects to the Safelist and adding a check for matches.

I propose adding both per-tag and global attribute wildcards.

Code to follow.

[jhy]

Thanks -- also as discussed in #499. I plan to implement wildcards in #2284.