Update maths/fast_inverse_sqrt.py

Co-authored-by: Christian Clauss <cclauss@me.com>

Author: aryanshb

maths/fast_inverse_sqrt.py

@@ -6,7 +6,7 @@
 import struct
 
 
-def fastInvSqrt(x: float) -> float:
+def fast_inverse_sqrt(x: float) -> float:
     """
     Calculate the fast inverse square root of a number.