Make sure that constructing an empty `StepMap` returns `StepMap.empty`.
1.3.3
Bug fixes
Fix an inconsistency in `deleteRange` where it would delete the parent node for ranges covering all textblocks in a given parent.
1.3.2
Bug fixes
Fix a regression in `dropPoint` that caused it to dereference undefined in some circumstances.
1.3.1
Bug fixes
Fix a crash in `Transform.replaceRange` when called with under specific circumstances.
Fix an issue where `dropPoint` could return an invalid drop point.
1.3.0
New features
`ContentMatch` objects now have an [`edgeCount`](https://prosemirror.net/docs/ref/#model.ContentMatch.edgeCount) property and an [`edge`](https://prosemirror.net/docs/ref/#model.ContentMatch.edge) method, providing direct access to the finite automaton structure.
1.2.12
Bug fixes
Fix a bug where merging replace steps with the `structure` flag could create steps that couldn't be applied.