invalid escape sequence SyntaxWarnings in docstrings

[iansimon]

As of Python 3.12, some of the docstrings contain escape sequences that are considered invalid and yield SyntaxWarnings:

• 2\pi in sonify.py
• \* in hierarchy.py and util.py
• \% in beat.py

Not sure if worth fixing yet, but apparently these will become SyntaxErrors in the future...

[tkoeppe]

In sonify.py I would just say 2π-periodic without any special maths markup. It seems clear enough.

[bmcfee]

Definitely worth fixing!

I'd second @tkoeppe 's suggestion of dropping the sphinx/reST cruft in favor of unicode. That doesn't necessarily help with the \* or \%, but I think that's probably unnecessary in the first place.

@iansimon do you know if it's possible to add an action to the docs testing CI that would check for this sort of thing?

[tkoeppe]

I'm not sure if these \% and \* were in support of some other doc processing system, but very naively thinking I'd just remove the backslashes and that would look like what I'd expect?