doc:openapi Improve documentation on spec's nodeId (#2084)

* This PR is for #2083
- adds more example and details on what nodeId.
- updated description of the nodeId.

Signed-off-by: howardyoo <howardyoo@gmail.com>

* fixed the example part of the nodId

Signed-off-by: howardyoo <howardyoo@gmail.com>

Signed-off-by: howardyoo <howardyoo@gmail.com>

spec/openapi.yml

@@ -697,7 +697,9 @@ components:
       schema:
         type: string
         example: dataset:food_delivery:public.delivery_7_days
-      description: The ID of the node.
+      description: The ID of the node. A node can either be a dataset node or a job node. The format of
+        nodeId for dataset is `dataset:<namespace_of_dataset>:<name_of_the_dataset>` and for job is
+        `job:<namespace_of_the_job>:<name_of_the_job>`.
       required: true
 
     depth:
@@ -1768,8 +1770,10 @@ components:
           example: food_delivery
         nodeId:
           type: string
-          description: The ID of the dataset or job node.
-          example: dataset:food_delivery:public.delivery_7_days
+          description: The ID of the node. A node can either be a dataset node or a job node. The format of
+            nodeId for dataset is `dataset:<namespace_of_dataset>:<name_of_the_dataset>` and for job is
+            `job:<namespace_of_the_job>:<name_of_the_job>`.
+          example: 'dataset:food_delivery:public.delivery_7_days'
 
     SearchResultType:
       type: enum