improve changelog documentation for irep_node changes
improve changelog documentation for irep_node changes

xuorig/graphql-ruby,rmosolgo/graphql-ruby,nevesenin/graphql-ruby,nevesenin/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,rmosolgo/graphql-ruby,nevesenin/graphql-ruby,xuorig/graphql-ruby,xuorig/graphql-ruby,rmosolgo/graphql-ruby