Server options file rename [TBR].

pkg/analysis_server/lib/src/server_options.dart

 // Copyright (c) 2015, 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.
 
 library analysis_server.src.server_options;
 
 import 'dart:collection';
 import 'dart:io';
 
 import 'package:path/path.dart' as path;
 import 'package:yaml/yaml.dart';
 
-const _optionsFileName = 'dart_analysis_server.options';
+//TODO: consider renaming (https://github.com/dart-lang/sdk/issues/23927)
+const _optionsFileName = '.dart_analysis_server.yaml';
 
 /// The shared options instance.
 ServerOptions _serverOptions;
 
 /// Server options.
 ServerOptions get serverOptions {
   if (_serverOptions == null) {
     _serverOptions = _loadOptions();
   }
   return _serverOptions;
@@ skipping 77 matching lines @@
     var doc = loadYaml(contents);
     if (doc is YamlMap) {
       doc.forEach((k, v) {
         if (k is String) {
           _options[k] = v;
         }
       });
     }
   }
 }