Update deprecations.

lib/src/md5.dart

 // Copyright (c) 2012, 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.
 
 import 'dart:convert';
 import 'dart:typed_data';
 
 import 'digest.dart';
 import 'hash.dart';
 import 'hash_sink.dart';
@@ skipping 14 matching lines @@
 /// [rfc]: https://tools.ietf.org/html/rfc1321
 ///
 /// **Warning**: MD5 has known collisions and should only be used when required
 /// for backwards compatibility.
 ///
 /// Note that it's almost always easier to use [md5] rather than creating a new
 /// instance.
 class MD5 extends Hash {
   final int blockSize = 16 * bytesPerWord;
 
-  @Deprecated("Use the md5 field instead.")
+  /// This constructor is deprecated.
+  ///
+  /// Use [md5] instead.
+  @Deprecated("Will be removed in crypto 1.0.0.")
   MD5();
 
   MD5 newInstance() => new MD5();
 
   ByteConversionSink startChunkedConversion(Sink<Digest> sink) =>
       new ByteConversionSink.from(new _MD5Sink(sink));
 }
 
 /// Data from a non-linear mathematical function that functions as
 /// reproducible noise.
@@ skipping 72 matching lines @@
               _shiftAmounts[i]));
       a = temp;
     }
 
     digest[0] = add32(a, digest[0]);
     digest[1] = add32(b, digest[1]);
     digest[2] = add32(c, digest[2]);
     digest[3] = add32(d, digest[3]);
   }
 }