censor: extract the part about writing the censored revision in a function The v2_censor function is huge, now that its content has settled a bit it is a good time to split individual part inside dedicated function. We start with a small function that process the censored revision. Differential Revision: https://phab.mercurial-scm.org/D10898

censor: put the tuple of open files in an explicit variable This will be simpler to pass these file around in future changesets. Differential Revision: https://phab.mercurial-scm.org/D10897

revlog: rewrite `censors.py` to `rewrite.py` The logic we use for censoring revision will be mostly common with the one we needs for stripping. So we rename the module to `rewrite` to better match its future content. Differential Revision: https://phab.mercurial-scm.org/D10896

copies: Keep changelog sidedata file open during copy tracing Instead of having a callback that opens and closes that file many times, a add and use a context manager method on the `revlog` class that keeps files open for its duration. Differential Revision: https://phab.mercurial-scm.org/D10888

purge: restore the `testedwith` declaration Otherwise, this extension gets highlighted as a 3rd party extension when an exception occurs. Differential Revision: https://phab.mercurial-scm.org/D10895

rust: remove dead utils module This was introduced a while back while not being imported anywhere in the module system. How pertinent this Facebook module was to the codebase was debatable at the time, nowadays with the Rust VFS layer having laid its foundations, it is clear that we should drop it. Differential Revision: https://phab.mercurial-scm.org/D10890