More BCDesque test data for text semantics (mark, ins, s, del)

[Elchi3]

Again, untested fiction data (half truth, I guess, given the PRs that were filed with BCD recently contained this information, so somewhat realistic).

The idea here would be:

• The keys sit under acd.html.elements.del, acd.html.elements.ins, etc. sharing the same namespace as bcd.html.elements.del and therefore complementing the BCD information.
• The keys are tagged with the web-feature they belong to (allowing future baseline calc if one wants to)
• "safari/voiceover_macos" is the browser/AT combination where we have data
• "18/1" are the version numbers for said browser/AT software.
• I used an array support statement to basically say: All is fine between Safari 5.1 and Safari 17.6 but from Safari 18 onwards, we have a failure which I categorized, described and linked to the bug.

Thoughts? Feedback?