Simple, replace sin with 1/cosec everywhere!

IIUC, copying over RustPython parser is an interesting detail, but that change happened earlier (2023!) when they were building Ruff, so it is old news. This piece of code called red-knot seems to be mostly original work, as far as I can tell.

https://github.com/astral-sh/ruff/issues?q=is%3Aopen+label%3Ared-knot+sort%3Acreated-asc