Update interfaces/webrtc.idl (#12468)

Copied by https://github.com/foolip/wpt-idl-importer from:
https://github.com/tidoust/reffy-reports/blob/bd06a9e/whatwg/idl/webrtc.idl
diff --git a/interfaces/webrtc.idl b/interfaces/webrtc.idl
index 2849a7d..c06e91e 100644
--- a/interfaces/webrtc.idl
+++ b/interfaces/webrtc.idl
@@ -1,7 +1,7 @@
 // GENERATED CONTENT - DO NOT EDIT
-// Content of this file was automatically extracted from the
-// "WebRTC 1.0: Real-time Communication Between Browsers" spec.
-// See: https://w3c.github.io/webrtc-pc/
+// Content was automatically extracted by Reffy into reffy-reports
+// (https://github.com/tidoust/reffy-reports)
+// Source: WebRTC 1.0: Real-time Communication Between Browsers (https://w3c.github.io/webrtc-pc/)
 
 dictionary RTCConfiguration {
              sequence<RTCIceServer> iceServers;
@@ -105,7 +105,7 @@
     readonly        attribute RTCSessionDescription? remoteDescription;
     readonly        attribute RTCSessionDescription? currentRemoteDescription;
     readonly        attribute RTCSessionDescription? pendingRemoteDescription;
-    Promise<void> addIceCandidate((RTCIceCandidateInit or RTCIceCandidate) candidate);
+    Promise<void> addIceCandidate(RTCIceCandidateInit candidate);
     readonly        attribute RTCSignalingState signalingState;
     readonly        attribute RTCIceGatheringState iceGatheringState;
     readonly        attribute RTCIceConnectionState iceConnectionState;
@@ -129,7 +129,7 @@
     Promise<void> setLocalDescription(RTCSessionDescriptionInit description, VoidFunction successCallback, RTCPeerConnectionErrorCallback failureCallback);
     Promise<void> createAnswer(RTCSessionDescriptionCallback successCallback, RTCPeerConnectionErrorCallback failureCallback);
     Promise<void> setRemoteDescription(RTCSessionDescriptionInit description, VoidFunction successCallback, RTCPeerConnectionErrorCallback failureCallback);
-    Promise<void> addIceCandidate((RTCIceCandidateInit or RTCIceCandidate) candidate, VoidFunction successCallback, RTCPeerConnectionErrorCallback failureCallback);
+    Promise<void> addIceCandidate(RTCIceCandidateInit candidate, VoidFunction successCallback, RTCPeerConnectionErrorCallback failureCallback);
 };
 
 callback RTCPeerConnectionErrorCallback = void (DOMException error);