Fix stream directive validation error message

Replicates graphql/graphql-js@8e9813f

Author: Cito

src/graphql/validation/rules/defer_stream_directive_on_valid_operations_rule.py

@@ -80,6 +80,6 @@ def enter_directive(
                 if not if_argument_can_be_false(node):
                     msg = (
                         "Stream directive not supported on subscription operations."
-                        " Disable `@defer` by setting the `if` argument to `false`."
+                        " Disable `@stream` by setting the `if` argument to `false`."
                     )
                     self.report_error(GraphQLError(msg, node))

tests/validation/test_defer_stream_directive_on_valid_operations.py

@@ -274,7 +274,7 @@ def stream_on_subscription_field():
                 {
                     "message": "Stream directive not supported"
                     " on subscription operations."
-                    " Disable `@defer` by setting the `if` argument to `false`.",
+                    " Disable `@stream` by setting the `if` argument to `false`.",
                     "locations": [(4, 26)],
                 },
             ],
@@ -296,7 +296,7 @@ def stream_on_fragment_on_subscription_field():
                 {
                     "message": "Stream directive not supported"
                     " on subscription operations."
-                    " Disable `@defer` by setting the `if` argument to `false`.",
+                    " Disable `@stream` by setting the `if` argument to `false`.",
                     "locations": [(8, 24)],
                 },
             ],
@@ -344,7 +344,7 @@ def stream_on_subscription_in_multi_operation_document():
                 {
                     "message": "Stream directive not supported"
                     " on subscription operations."
-                    " Disable `@defer` by setting the `if` argument to `false`.",
+                    " Disable `@stream` by setting the `if` argument to `false`.",
                     "locations": [(15, 24)],
                 },
             ],