Bug 1598405 [wpt PR 20365] - Update interfaces/audio-output.idl, a=testonly

Automatic update from web-platform-tests
Update interfaces/audio-output.idl (#20365)

Source: https://github.com/tidoust/reffy-reports/blob/fea9670/ed/idl/audio-output.idl
Build: https://travis-ci.org/tidoust/reffy-reports/builds/615198653
--

wpt-commits: 046be8103f70948c7e56100aceb9f8c52638d6e9
wpt-pr: 20365

testing/web-platform/tests/interfaces/audio-output.idl

@@ -5,5 +5,5 @@
 
 partial interface HTMLMediaElement {
   [SecureContext] readonly attribute DOMString sinkId;
-  [SecureContext] Promise<void> setSinkId(DOMString sinkId);
+  [SecureContext] Promise<void> setSinkId (DOMString sinkId);
 };