Update spec/Section 6 -- Execution.md

Co-authored-by: Benjie <benjie@jemjie.com>

Author: robrichard

spec/Section 6 -- Execution.md

@@ -834,6 +834,6 @@ resolves to {null}, then the entire list must resolve to {null}. If the `List`
 type is also wrapped in a `Non-Null`, the field error continues to propagate
 upwards.
 
-If all response positions from the root of the request to the source of the
-field error return `Non-Null` types, then the {"data"} entry in the response
+If every _response position_ from the root of the request to the source of the
+field error returns a `Non-Null` type, then the {"data"} entry in the response
 should be {null}.