test_schema_parser: Adapt description of a test case

Replicates graphql/graphql-js@9d9f606

Author: Cito

tests/language/test_schema_parser.py

@@ -174,7 +174,7 @@ def parses_type_with_description_multi_line_string():
         assert description.block is True
         assert description.loc == (1, 20)
 
-    def reject_description_followed_by_non_type_system_definition():
+    def description_followed_by_something_other_than_type_system_definition_throws():
         assert_syntax_error('"Description" 1', "Unexpected Int '1'.", (1, 15))
 
     def simple_extension():