mention headers in canonical form (#1232)

Author: costela

src/data/markdown/docs/02 javascript api/09 k6-http/61 Response.md

@@ -14,7 +14,7 @@ Note that in the case of redirects, all the information in the Response object w
 | `Response.cookies`                                                                             | object   | Response cookies. The object properties are the cookie names and the value is an array of cookie objects (with `name`, `value`, `domain`, `path`, `httpOnly`, `secure`, `maxAge` and `expires` fields).                                                                                                                                                                                                                                                                                                                     |
 | `Response.error`                                                                               | string   | Error message if there was a non-HTTP error while trying to send the request.                                                                                                                                                                                                                                                                                                                                                                                                                                               |
 | `Response.error_code`                                                                          | number   | [Error code](/javascript-api/error-codes) if there was a non-HTTP error or 4xx or 5xx HTTP error it will be set to a specific code that describes the error. (Added in 0.24.0)                                                                                                                                                                                                                                                                                                                                              |
-| `Response.headers`                                                                             | object   | Key-value pairs representing all HTTP headers sent by the server.                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
+| `Response.headers`                                                                             | object   | Key-value pairs representing all HTTP headers sent by the server. Note that the header names are in [canonical form](https://pkg.go.dev/net/http#CanonicalHeaderKey), i.e.: if the server responds with "accept-encoding", the key will be "Accept-Encoding".                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
 | `Response.ocsp.produced_at`                                                                    | number   | If a stapled OSCP response was provided by server, the number of milliseconds elapsed since 1 January 1970 00:00:00 UTC, representing the time when this OCSP stapled response was signed by CA (or by CA entrusted OCSP responder)                                                                                                                                                                                                                                                                                         |
 | `Response.ocsp.this_update`                                                                    | number   | If a stapled OSCP response was provided by server, the number of milliseconds elapsed since 1 January 1970 00:00:00 UTC, representing the time at which the status being indicated was known to be correct.                                                                                                                                                                                                                                                                                                                 |
 | `Response.ocsp.next_update`                                                                    | number   | If a stapled OSCP response was provided by server, the number of milliseconds elapsed since 1 January 1970 00:00:00 UTC, representing the time when this OCSP stapled response will be refreshed with CA (or by CA entrusted OCSP responder).                                                                                                                                                                                                                                                                               |