Bring dartfmt 1.0.1 (now 1.0.2) into the SDK.

CHANGELOG.md

 ## 1.23.0
 
 ### Language
 * Allow using URI strings in `part of` declarations to refer to the
   importing library.
 
 ### Core library changes
 
 * `dart:core`
   * Added `Uri.isScheme` function to check the scheme of a URI.
@@ skipping 19 matching lines @@
 * Strong mode will prefer the expected type to infer generic types,
   functions, and methods
   (SDK issue [27586](https://github.com/dart-lang/sdk/issues/27586)).
 
   ```dart
   main() {
     List<Object> foo = /*infers: <Object>*/['hello', 'world'];
     var bar = /*infers: <String>*/['hello', 'world'];
   }
   ```
-  
+
 * Strong mode inference error messages are improved
   (SDK issue [29108](https://github.com/dart-lang/sdk/issues/29108)).
 
   ```dart
   import 'dart:math';
   test(Iterable/* fix is to add <num> here */ values) {
     num n = values.fold(values.first as num, max);
   }
   ```
   Now produces the error on the generic function "max":
@@ skipping 64 matching lines @@
       uploaded with the user and group names set to "pub".
     * No longer fails with a stack overflow when uploading a package that uses
       Git submodules.
   * `pub get` and `pub upgrade`
     * Produce more informative error messages if they're run directly in a
       package that uses Flutter.
     * Properly unlock SDK and path dependencies if they have a new version
       that's also valid according to the user's pubspec.
 
 * dartfmt
+  * Support new generic function typedef syntax.
   * Make the precedence of cascades more visible.
   * Fix a couple of places where spurious newlines were inserted.
   * Correctly report unchanged formatting when reading from stdin.
+  * Ensure space between `-` and `--`. Code that does this is pathological, but
+    it technically meant dartfmt could change the semantics of the code.
+  * Preserve a blank line between enum cases.
   * Other small formatting tweaks.
 
 ## 1.22.0
 
 ### Language
 
   * Breaking change:
     ['Generalized tear-offs'](https://github.com/gbracha/generalizedTearOffs/blob/master/proposal.md)
     are no longer supported, and will cause errors. We updated the language spec
     and added warnings in 1.21, and are now taking the last step to fully
@@ skipping 1656 matching lines @@
     they will keep the Dart process alive until they time out. This fixes the
     handling of persistent connections. Previously, the client would shut down
     immediately after a request.
 
   * **Breaking change:** `HttpServer` no longer compresses all traffic by
     default. The new `autoCompress` property can be set to `true` to re-enable
     compression.
 
 * `dart:isolate`: `Isolate.spawnUri` added the optional `packageRoot` argument,
   which controls how it resolves `package:` URIs.