revset: drop some unused code in the `remote` revset PyCharm flagged the `revs = [..]` as an unused assignment. But then neither `revs` nor `checkout` is used, and I can't see where `hg.addbranchrevs()` has external side effects. Differential Revision: https://phab.mercurial-scm.org/D7764

tests: avoid using a list comprehension to fill a list with fixed values Flagged by PyCharm as an unused assignment for the variable in the list. Differential Revision: https://phab.mercurial-scm.org/D7763

histedit: avoid using a list comprehension to fill a list with fixed values Flagged by PyCharm as an unused assignment for the variable in the list. Differential Revision: https://phab.mercurial-scm.org/D7762

zstandard: vendor python-zstandard 0.13.0 Version 0.13.0 of the package was just released. It contains an upgraded zstd C library which can result in some performance wins, official support for Python 3.8, and a blackened code base. There were no meaningful code or functionality changes in this release of python-zstandard: just reformatting and an upgraded zstd library version. So the diff seems much larger than what it is. Files were added without modifications. The clang-format-ignorelist file was updated to reflect a new header file in the zstd distribution. # no-check-commit because 3rd party code has different style guidelines Differential Revision: https://phab.mercurial-scm.org/D7770

hgweb: delete a local variable instead of setting to `None` The previous code was flagged by PyCharm as an unused variable assignment. Differential Revision: https://phab.mercurial-scm.org/D7761

tests: drop unused local variable assignments in linelog Flagged by PyCharm. Differential Revision: https://phab.mercurial-scm.org/D7760