docs: fix highlights, add missing code annotation

docs/core/event_handler/appsync.md

@@ -379,16 +379,16 @@ In this mode, you must return results in the same order of your batch items, so
     2. We use `post_id` as our unique identifier of the GraphQL request.
 
 === "getting_started_with_batch_resolver_payload.json"
-  	```json hl_lines="4 16 21 29 41 46"
+  	```json hl_lines="6 16 25 35 44 54"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_resolver_payload.json"
   	```
 
 === "getting_started_with_batch_query.graphql"
-  	```typescript hl_lines="4 16 21 29 41 46"
+  	```typescript hl_lines="3 6"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_query.graphql"
   	```
 
-#### Processing items individually
+##### Processing items individually
 
 ```mermaid
 stateDiagram-v2
@@ -446,20 +446,20 @@ In this mode, we will:
     * You can customize `nul` or error responses back to the client in the [AppSync resolver mapping templates](https://docs.aws.amazon.com/appsync/latest/devguide/tutorial-lambda-resolvers.html#returning-individual-errors){target="_blank"}
 
 === "getting_started_with_batch_resolver_individual.py"
-  	```python hl_lines="3 7 17"
+  	```python hl_lines="5 9 19"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_resolver_individual.py"
   	```
 
     1. You need to disable the aggregated event by using `aggregate` flag.
         The resolver receives and processes each record one at a time.
 
 === "getting_started_with_batch_resolver_payload.json"
-  	```json hl_lines="4 16 21 29 41 46"
+  	```json hl_lines="6 16 25 35 44 54"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_resolver_payload.json"
   	```
 
 === "getting_started_with_batch_query.graphql"
-  	```typescript hl_lines="4 16 21 29 41 46"
+  	```typescript hl_lines="3 6"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_query.graphql"
   	```
 
@@ -520,38 +520,40 @@ You can toggle `raise_on_error` parameter in `@batch_resolver` to propagate any
 This is useful when you want to stop processing immediately in the event of an unhandled or unrecoverable exception.
 
 === "getting_started_with_batch_resolver_handling_error.py"
-  	```python hl_lines="3 7 17"
+  	```python hl_lines="5 9 19"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_resolver_handling_error.py"
   	```
 
     1. You can enable enable the error handling by using `raise_on_error` flag.
 
 === "getting_started_with_batch_resolver_payload.json"
-  	```json hl_lines="4 16 21 29 41 46"
+  	```json hl_lines="6 16 25 35 44 54"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_resolver_payload.json"
   	```
 
 === "getting_started_with_batch_query.graphql"
-  	```typescript hl_lines="4 16 21 29 41 46"
+  	```typescript hl_lines="3 6"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_query.graphql"
   	```
 
-#### Async
+#### Async batch resolver
 
 Similar to `@batch_resolver` explained in [batch resolvers](#batch-resolvers), you can use `async_batch_resolver` to handle async functions.
 
 === "getting_started_with_batch_async_resolver.py"
-  	```python hl_lines="3 7 17"
+  	```python hl_lines="5 9 23"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_async_resolver.py"
   	```
 
-=== "getting_started_with_batch_async_resolver_payload.json"
-  	```json hl_lines="4 16 21 29 41 46"
-    --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_async_resolver_payload.json"
+    1. `async_batch_resolver` takes care of running and waiting for coroutine completion.
+
+=== "getting_started_with_batch_resolver_payload.json"
+  	```json hl_lines="6 16 25 35 44 54"
+    --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_resolver_payload.json"
   	```
 
 === "getting_started_with_batch_query.graphql"
-  	```typescript hl_lines="4 16 21 29 41 46"
+  	```typescript hl_lines="3 6"
     --8<-- "examples/event_handler_graphql/src/getting_started_with_batch_query.graphql"
   	```
 

examples/event_handler_graphql/src/getting_started_with_batch_async_resolver.py

@@ -21,9 +21,9 @@ async def search_batch_posts(posts: list) -> dict[str, Any]:
 
 
 @app.async_batch_resolver(type_name="Query", field_name="relatedPosts")
-async def related_posts(event: list[AppSyncResolverEvent]) -> list[Any]:  # (1)!
+async def related_posts(event: list[AppSyncResolverEvent]) -> list[Any]:
     # Extract all post_ids in order
-    post_ids: list = [record.source.get("post_id") for record in event]  # (2)!
+    post_ids: list = [record.source.get("post_id") for record in event]
 
     # Get unique post_ids while preserving order
     unique_post_ids = list(dict.fromkeys(post_ids))
@@ -36,4 +36,4 @@ async def related_posts(event: list[AppSyncResolverEvent]) -> list[Any]:  # (1)!
 
 
 def lambda_handler(event, context: LambdaContext) -> dict:
-    return app.resolve(event, context)
+    return app.resolve(event, context)  # (1)!