Generated by autopep8, with the setup.cfg configuration from #14532.
I’m not sure why pycodestyle didn’t already flag these.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>
Previously, the send_custom_email code path leaked files in paths that
were not `.gitignored`, under templates/zerver/emails.
This became problematic when we added automated tests for this code
path, as it meant we leaked these files every time `test-backend` ran.
Fix this by ensuring all the files we generate are in this special
subdirectory.