Update coulombs_law.py docs (#9667)

* Update coulombs_law.py

distance is positive non zero real number (float type) hence corrected docs which says only integer.

* Update physics/coulombs_law.py

---------

Co-authored-by: Tianyi Zheng <[email protected]>

Author: Raghav-Bell

Diff for: physics/coulombs_law.py

@@ -32,7 +32,7 @@ def coulombs_law(q1: float, q2: float, radius: float) -> float:
     17975103584.6
     """
     if radius <= 0:
-        raise ValueError("The radius is always a positive non zero integer")
+        raise ValueError("The radius is always a positive number")
     return round(((8.9875517923 * 10**9) * q1 * q2) / (radius**2), 2)