Use dartfmt on Observatory code

runtime/observatory/lib/src/models/objects/breakpoint.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of models;
 
 abstract class Breakpoint extends Object {
   /// A number identifying this breakpoint to the user.
   int get number;
+
   /// Has this breakpoint been assigned to a specific program location?
   bool get resolved;
+
   /// [optional]Is this a breakpoint that was added synthetically as part of a
   /// step OverAsyncSuspension resume command?
   bool get isSyntheticAsyncContinuation;
+
   /// SourceLocation when breakpoint is resolved, UnresolvedSourceLocation
   /// when a breakpoint is not resolved.
   Location get location;
 }