Provide direction to users of the now deprecated class FileUriResolver

pkg/analyzer/lib/src/generated/source_io.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 analyzer.src.generated.source_io;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_core.dart';
@@ skipping 244 matching lines @@
   String toString() {
     if (file == null) {
       return "<unknown source>";
     }
     return file.getAbsolutePath();
   }
 }
 
 /**
  * Instances of the class `FileUriResolver` resolve `file` URI's.
+ *
+ * This class is now deprecated, 'new FileUriResolver()' is equivalent to
+ * 'new ResourceUriResolver(PhysicalResourceProvider.INSTANCE)'.
  */
 @deprecated
 class FileUriResolver extends UriResolver {
   /**
    * The name of the `file` scheme.
    */
   static String FILE_SCHEME = "file";
 
   @override
   Source resolveAbsolute(Uri uri, [Uri actualUri]) {
@@ skipping 235 matching lines @@
    * Return `true` if the given URI is a `package` URI.
    *
    * @param uri the URI being tested
    * @return `true` if the given URI is a `package` URI
    */
   static bool isPackageUri(Uri uri) => PACKAGE_SCHEME == uri.scheme;
 }
 
 /**
  * Instances of the class `RelativeFileUriResolver` resolve `file` URI's.
+ *
+ * This class is now deprecated, file URI resolution should be done with
+ * ResourceUriResolver, i.e.
+ * 'new ResourceUriResolver(PhysicalResourceProvider.INSTANCE)'.
  */
 @deprecated
 class RelativeFileUriResolver extends UriResolver {
   /**
    * The name of the `file` scheme.
    */
   static String FILE_SCHEME = "file";
 
   /**
    * The directories for the relatvie URI's
@@ skipping 29 matching lines @@
   }
 
   /**
    * Return `true` if the given URI is a `file` URI.
    *
    * @param uri the URI being tested
    * @return `true` if the given URI is a `file` URI
    */
   static bool isFileUri(Uri uri) => uri.scheme == FILE_SCHEME;
 }