And I forgot, why is one commit marked s feat! (breaking change)? This crate uses it only for breaking API changes, which doesn't seem to be the case here.
If it is no breaking change, could you change the commit by removing the !?

And bonus points for a specific unit test so this change isn't 'only' tested by the quite broad stupicat fixture based test.

Thanks again.

Good catch 👍 The !s have been removed.

As for event-splitting, try running this from the pulldown-cmark repository:

$ cargo run --example events
lucky*star
 
lucky\*star

"lucky*star\n\nlucky\\*star\n" -> [
  Start(Paragraph)
    Text(Borrowed("lucky"))
    Text(Borrowed("*"))
    Text(Borrowed("star"))
  End(Paragraph)
  Start(Paragraph)
    Text(Borrowed("lucky"))
    Text(Borrowed("*star"))
  End(Paragraph)
]

These two paragraphs mean the same thing, but the text events are different. The spec.txt test suite contains a lot of this stuff, because the whole point of the thing is to demonstrate corner cases in CommonMark. To make sure the event stream was identical, we'd need to avoid spurious backslash escapes, even if the library user has edited the event stream to insert their own text nodes with asterisks in them.

And here is the new release - it turns out there were other breaking changes before it: https://github.com/Byron/pulldown-cmark-to-cmark/releases/tag/v18.0.0