Generated by `pyupgrade --py3-plus --keep-percent-format` on all our
Python code except `zthumbor` and `zulip-ec2-configure-interfaces`,
followed by manual indentation fixes.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
These are the straightforward ones.
Note that there is a line in zerver.lib.test_classes.build_webhook_url
that lost test coverage. That's because most of our tests test using
stream messages so the webhook URLs being tested always have a query
parameter. So the line that accounts for there being no query
parameters never gets called, which is fine, but we should still
keep it.