## Summary
If you want to create an edit with dynamic applicability, you have to
branch and repeat the edit entirely between the two branches. If you
further need the edit itself to be dynamic (e.g., perhaps you have a
single edit in one case, vs. multiple in another), you suddenly have
four branches. This PR just adds an alternate constructor that takes
applicability as an argument, as an escape hatch.
5e2bb8ca07