histedit: factor out logic of processing state data in separate fn The new function will serve as the point from where we always get a dictionary of data stored in the statefile and will be helpful in integrating state.cmdstate.read() to write statefile in cbor. Differential Revision: https://phab.mercurial-scm.org/D3863

histedit: use hg.updaterepo() to avoid ui.{push|pop}buffer() hack In some parts of code, we call hg.update() and surround that with ui.pushbuffer() and ui.popbuffer() to suppress the output returned by hg.update(). We have hg.updaterepo() which does not writes to UI and can be used instead. Differential Revision: https://phab.mercurial-scm.org/D3862