More similar to prior wording

Author: benjie

spec/Section 6 -- Execution.md

@@ -369,9 +369,9 @@ Before execution, the _selection set_ is converted to a _grouped field set_ by
 calling {CollectFields()}.
 
 :: A _grouped field set_ is a map where each entry is a list of field selections
-(including those in referenced fragments) that share a _response key_ (the alias
-if defined, otherwise the field name). This ensures all fields with the same
-_response key_ are executed at the same time.
+that share a _response key_ (the alias if defined, otherwise the field name).
+This ensures all fields with the same response key (including those in
+referenced fragments) are executed at the same time.
 
 As an example, collecting the fields of this selection set would collect two
 instances of the field `a` and one of field `b`: