message: Clarify `x-ms-identifiers` documentation
  * Update readme.md
  Make it clear if there is "id" property in the object model, then there is no need to add the x-ms-identifiers annotation.
  * Update readme.md
diff: @@ -1378,10 +1378,10 @@ This extension is used to annotate the secret property. The value type is boolea
  **Rule**
  -- The default identifying property is `id`.
  +- The default identifying property is `id`. You don't need to add this annotataion if there is the `id` property in the object model.
  - If there is no appropriate identifying properties, leave it as an empty array.
  - You can provide multiple properties to form the composite identifier.
  -- User [json pointer](https://datatracker.ietf.org/doc/html/rfc6901) if the identifying property is an inner property. E.g., `/properties/subnet/id`
  +- Use [json pointer](https://datatracker.ietf.org/doc/html/rfc6901) if the identifying property is an inner property. E.g., `"x-ms-identifiers": ["/properties/subnet/id"]`
  **Schema**:
  `array`
  