fix: add byte literals with characters up to utf-32be

[jvllmr]

Hi,

First of all, big thanks for this project. I use it for fuzzing in my newly created rustpython-unparser library and it helped me a lot with reaching a satisfying result fast.

However, when using my unparser with real world code bases I realised that it couldn't handle byte literals that contain non-utf-8 characters. Therefore, I thought it would be good if pysource-codegen outputs code with such byte literals so that such errors can be catched by fuzzing in the future. The examples I added come from the pygments.lexer module.

[15r10nk]

Thank you for this examples.