Add support for Py 3.13

[facelessuser]

• Support Py 3.13
• Remove deprecated raw_escape
• Remove casting which incurs a performance cost for little gain. Once that cannot easily be resolved, just ignore the mypy error.
• Update formatted strings to f-string (where possible)

[facelessuser]

The niche, deprecated function that we are removing can replicated via the code below. I want to document it here in case there are questions about it.

def raw_escape(pattern: AnyStr, unix: bool | None = None, raw_chars: bool = True) -> AnyStr:
    """
    Escape a raw string as if it was a normal string.

    pattern: pattern to escape.
    unix: True or False to force Unix or Windows mode, None to allow detection based on system.
    raw_chars: Process raw string and convert Python escaped Unicode or ASCII characters.
    """

    import codecs

    if isinstance(pattern, bytes):
        pattern = pattern.replace(b'\\\\', b'\\') if not raw_chars else codecs.escape_decode(pattern)[0]
    else:
        pattern = pattern.replace('\\\\', '\\') if not raw_chars else codecs.unicode_escape_decode(pattern)[0]

    return escape(pattern, unix=unix)

[facelessuser]

@gir-bot lgtm