Update take operator (#240)

Author: tothmano

apl/tabular-operators/take-operator.mdx

@@ -54,7 +54,7 @@ SELECT * FROM sample_http_logs LIMIT 10;
 
 ### Parameters
 
-- `N`: The number of rows to take from the dataset. If `N` is positive, it returns the first `N` rows. If `N` is negative, it returns the last `N` rows.
+- `N`: The number of rows to take from the dataset. `N` must be a positive integer.
 
 ### Returns