[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

maths/gcd.py

@@ -18,4 +18,4 @@ def gcd(a: int, b: int) -> int:
     :param a: first integer
     :param b: second integer
     :return: greatest common divisor of a and b
-    """
+    """