fix(docs): improve the doc by providing sample inputs

src/main/java/io/kestra/plugin/mongodb/Bulk.java

@@ -29,7 +29,15 @@
 @Getter
 @NoArgsConstructor
 @Schema(
-    title = "Execute [Bulk](https://www.mongodb.com/docs/manual/reference/method/Bulk/) request in MongoDB."
+    title = "Execute [Bulk](https://www.mongodb.com/docs/manual/reference/method/Bulk/) request in MongoDB.",
+    description = """
+    Here are the sample file contents that can be provided as input to Bulk task:
+    ```
+    { "insertOne" : {"firstName": "John", "lastName": "Doe", "city": "Paris"}}
+    { "insertOne" : {"firstName": "Ravi", "lastName": "Singh", "city": "Mumbai"}}
+    { "deleteMany": {"filter": {"city": "Bengaluru"}}}
+    ```
+    """
 )
 @Plugin(
     examples = {