Bug 1598544 [wpt PR 20387] - Update interfaces/remote-playback.idl, a=testonly

Automatic update from web-platform-tests
Update interfaces/remote-playback.idl (#20387)

Source: https://github.com/tidoust/reffy-reports/blob/fea9670/ed/idl/remote-playback.idl
Build: https://travis-ci.org/tidoust/reffy-reports/builds/615198653
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wpt-commits: 565dea5285601ee8dde220e0d7021c5691cce7fa
wpt-pr: 20387

testing/web-platform/tests/interfaces/remote-playback.idl

@@ -23,7 +23,7 @@ enum RemotePlaybackState {
   "disconnected"
 };
 
-callback RemotePlaybackAvailabilityCallback = void (boolean available);
+callback RemotePlaybackAvailabilityCallback = void(boolean available);
 
 partial interface HTMLMediaElement {
   [SameObject] readonly attribute RemotePlayback remote;