[Contracts] fix phpdoc for http-client (user_data)

Author: gharlan

HttpClientInterface.php

@@ -39,7 +39,7 @@ interface HttpClientInterface
                                 //   the JSON-encoded value and set the "content-type" headers to a JSON-compatible
                                 //   value it is they are not defined - typically "application/json"
         'user_data' => null,    // mixed - any extra data to attach to the request (scalar, callable, object...) that
-                                //   MUST be available via $response->getInfo('data') - not used internally
+                                //   MUST be available via $response->getInfo('user_data') - not used internally
         'max_redirects' => 20,  // int - the maximum number of redirects to follow; a value lower or equal to 0 means
                                 //   redirects should not be followed; "Authorization" and "Cookie" headers MUST
                                 //   NOT follow except for the initial host name

ResponseInterface.php

@@ -86,7 +86,7 @@ public function toArray(bool $throw = true): array;
      *  - http_method - the HTTP verb of the last request
      *  - http_code - the last response code or 0 when it is not known yet
      *  - error - the error message when the transfer was aborted, null otherwise
-     *  - data - the value of the "data" request option, null if not set
+     *  - user_data - the value of the "user_data" request option, null if not set
      *  - url - the last effective URL of the request
      *
      * When the "capture_peer_cert_chain" option is true, the "peer_certificate_chain"