py3: drop redundant `u''` prefixes on string literals Strings are unicode on Python 3. These were rewritten by `pyupgrade`. It's arguably better to fix the `contrib` stuff upstream and then re-vendor it, but I don't feel like waiting for that, and then all of the regression testing involved to get a minor improvement in the codebase. It was last vendored 5 years ago, and will likely be a large change anyway to drop py2 support. Also, we've already made minor formatting changes to it locally.