windows: add windows behavior on broken pager Apparently, Windows has "better" behavior than Unix in this case. This is an edge case that led me down a rabbit hole, only to find a bug in the Python documentation... I am not planning on trying to reproduce the same behavior on Unix systems since it's not really useful, but other people are welcome to! Differential Revision: https://phab.mercurial-scm.org/D11000

mergestate: use dirstate.update_file API in recordupdates() Let's use the new single function to replace multiple different functions. This is part of dirstate API refactor to make it more clearer and generic so that it can be replicated in Rust. Differential Revision: https://phab.mercurial-scm.org/D11077