Fix typo in comment

csppfetch/roundtozero.py

@@ -22,7 +22,7 @@ def roundtozero(value, step = None, offset = None):
 
     If step is None, step is type(value)(1)
 
-    If offset is None, step is type(value)()
+    If offset is None, offset is type(value)()
 
     Should work with any number-like that supports addition, subtraction,
     division (returning a float), and multiplication against an integer.