Update sources/platform/actors/development/actor_definition/dataset_s…

…chema/validation.md

Co-authored-by: Michał Olender <92638966+TC-MO@users.noreply.github.com>

sources/platform/actors/development/actor_definition/dataset_schema/validation.md

@@ -217,7 +217,7 @@ The measured statistics are following:
   - For strings, this field tracks string length
   - For arrays, this field tracks the number of items in the array
   - For objects, this tracks the number of keys
-  - For booleans, this tracks whether the boolean was set to true. Minimum is always 0, but maximum can be either 1 or 0 based on whether at least on item in the dataset has the boolean field set to true.
+  - For booleans, this tracks whether the boolean was set to true. Minimum is always 0, but maximum can be either 1 or 0 based on whether at least one item in the dataset has the boolean field set to true.
 
 
 You can use them in [monitoring](../../../../monitoring#alert-configuration).