pipeline: inputs: http: Add threading info

Signed-off-by: Alexa Kreizinger <alexakreizinger@gmail.com>

Author: alexakreizinger

pipeline/inputs/http.md

@@ -15,6 +15,7 @@ description: The HTTP input plugin allows you to send custom records to an HTTP
 | buffer_chunk_size        | This sets the chunk size for incoming incoming JSON messages. These chunks are then stored/managed in the space available by buffer_max_size. | 512K    |
 | successful_response_code | It allows to set successful response code. `200`, `201` and `204` are supported.                                                              | 201     |
 | success_header           | Add an HTTP header key/value pair on success. Multiple headers can be set. Example: `X-Custom custom-answer`                                  |         |
+| threaded | Indicates whether to run this input in its own [thread](../../administration/multithreading.md#inputs). | false |
 
 ### TLS / SSL