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

Author: pre-commit-ci[bot]

Diff for: src/diffpy/utils/validators.py

@@ -1,6 +1,6 @@
 def is_number(string):
     """Check if the provided string can be converted to a float.
-    
+
     Since integers can be converted to floats, this function will return True for integers as well.
     Hence, we can use this function to check if a string is a number.