view mercurial/__init__.py @ 24765:bdf84cc2115b

histedit: add a new histeditaction class

This adds a new class called histeditaction. It represents a single action in a
histedit plan. Future patches will integrate it into the histedit flow, then
convert each existing action in to the class form one by one.

This is part of a larger refactor aimed at increasing histedit robustness,
maintainability, and extensibility.