MIDI docs: add missing bracket

The example code for openDevice() was missing a close bracket.

Bug: 25283941
Change-Id: I8fac6a6dee2393125ad4e057cb857fe21e43b491
Signed-off-by: Phil Burk <philburk@google.com>

media/java/android/media/midi/package.html

@@ -180,7 +180,8 @@ m.openDevice(info, new MidiManager.OnDeviceOpenedListener() {
             Log.e(TAG, "could not open device " + info);
         } else {
             ...
-        }, new Handler(Looper.getMainLooper())
+        }
+    }, new Handler(Looper.getMainLooper())
     );
 </pre>