chore: update description.markdown description (#1167)

README.md

@@ -383,7 +383,7 @@ When a short string in your documentation is insufficient, or you need images, c
 | annotation  | description                                                                                                                |
 |-------------|----------------------------------------------------------------------------------------------------------------------------|
 | description | A verbose explanation of the operation behavior.                                                                           |
-| description.markdown     |  A short description of the application. The description will be read from a file named like endpointname.md| // @description.file endpoint.description.markdown  |
+| description.markdown     |  A short description of the application. The description will be read from a file.  E.g. `@description.markdown details` will load `details.md`| // @description.file endpoint.description.markdown  |
 | id          | A unique string used to identify the operation. Must be unique among all API operations.                                   |
 | tags        | A list of tags to each API operation that separated by commas.                                                             |
 | summary     | A short summary of what the operation does.                                                                                |