clarify which key

proposals/2399-reporting-no-key-sent.md

@@ -31,7 +31,7 @@ the properties:
 - `algorithm`: Required. The encryption algorithm that the key is for.
 - `session_id`: Required if `code` is not `m.no_olm`. The ID of the session.
 - `sender_key`: Required.  The key of the session creator.
-- `code`: Required.  A machine-readable code for why the key was not sent.
+- `code`: Required.  A machine-readable code for why the megolm key was not sent.
   Possible values are:
   - `m.blacklisted`: the user/device was blacklisted
   - `m.unverified`: the user/devices is unverified