Make documentation and parameters consistant.

README.md

@@ -1753,7 +1753,7 @@ call legs, therefore all keys other than `call-id` are currently ignored.
 If the chosen recording method doesn't support in-kernel packet forwarding, enabling call recording
 via this messages will force packet forwarding to happen in userspace only.
 
-If the optional 'output-file' key is set, then its value will be used
+If the optional 'output-destination' key is set, then its value will be used
 as an output file. Note that a filename extension will not be added.
 
 `stop recording` Message

daemon/call_interfaces.c

@@ -1919,7 +1919,7 @@ const char *call_start_recording_ng(bencode_item_t *input, bencode_item_t *outpu
 	if (!bencode_dictionary_get_str(input, "call-id", &callid))
 		return "No call-id in message";
 	bencode_dictionary_get_str(input, "metadata", &metadata);
-	bencode_dictionary_get_str(input, "output_destination", &output_dest);
+	bencode_dictionary_get_str(input, "output-destination", &output_dest);
 	call = call_get_opmode(&callid, OP_OTHER);
 	if (!call)
 		return "Unknown call-id";