docs : graphql package 설정 설명 주석 추가

놀이터(예제 코드 작성)/graphql-kotlin/src/main/resources/application.yaml

@@ -1,3 +1,10 @@
+# At a minimum, in order for graphql-kotlin-spring-server to automatically configure your GraphQL web server
+#
+# you need to specify a list of supported packages that can be scanned for exposing your schema objects through reflections.
+#
+# You can do this through the spring application config or by overriding the SchemaGeneratorConfig bean.
+#
+# See customization below.
 graphql:
   packages:
     - "com.banjjoknim.graphqlkotlin"