Fixes UP032 crash with raw strings containing \N{

[IMaloney]

Fixes UP032 crash with raw strings containing \\N{ (#22060)

Here we are converting raw strings like r"\\N{angle}".format(angle=180) to f-strings. Converting to rf"\\N{angle}" makes the f-string try to evaluate {angle} as a variable instead of keeping it as format syntax, which causes NameError.

Let's add a check to skip conversion when raw strings contain \\N{ patterns.

Test Plan

Manual testing with the exact code from the issue:

# Before (crashes after ruff fix):
print(r"\\N{angle}AOB = {angle}°".format(angle=180))

# After (left unchanged, works correctly):
print(r"\\N{angle}AOB = {angle}°".format(angle=180))
# Output: \\N180AOB = 180°

Added test case to UP032_0.py fixture file.

[ntBre]

Thanks for working on this, but it looks like there's already an open PR for this issue: #22149. So I'll close this for now.