fix: parenthesize multiple exception types in greatest_common_divisor.py

[vishwagna]

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• Fix a bug or typo in an existing algorithm?
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Fixes #14929

Restores parenthesized syntax for multiple exception types in
maths/greatest_common_divisor.py. A ruff pre-commit autoupdate (#14325)
rewrote the previously-correct except (IndexError, UnboundLocalError, ValueError):
into invalid Python 3 syntax, causing a SyntaxError at import time and
breaking downstream imports in maths/least_common_multiple.py and
maths/primelib.py.

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