Use a raw string to correctly print \n in option description in the analysis server.

pkg/analysis_server/lib/src/server/driver.dart

 // Copyright (c) 2014, 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 driver;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:math';
 
@@ skipping 325 matching lines @@
         negatable: false);
     parser.addOption(
         FILE_READ_MODE,
         help: "an option of the ways files can be read from disk, " +
             "some clients normalize end of line characters which would make " +
             "the file offset and range information incorrect.",
         allowed: ["as-is", "normalize-eol-always"],
         allowedHelp: {
       "as-is": "file contents are read as-is, no file changes occur",
       "normalize-eol-always":
-          "file contents normalize the end of line characters to the single character new line `\n`"
+          r'file contents normalize the end of line characters to the single character new line `\n`'
     }, defaultsTo: "as-is");
 
     return parser;
   }
 
   /**
    * Print information about how to use the server.
    */
   void _printUsage(ArgParser parser) {
     print('Usage: $BINARY_NAME [flags]');
@@ skipping 26 matching lines @@
       uuidFile.parent.createSync(recursive: true);
       uuidFile.writeAsStringSync(uuid);
     } catch (exception, stackTrace) {
       service.logPriorityException(exception, stackTrace);
       // Slightly alter the uuid to indicate it was not persisted
       uuid = 'temp-$uuid';
     }
     return uuid;
   }
 }