Fix doc comment references that need prefixed doc imports (#193906)

Adds prefixed `@docImport` directives so that doc comment references
that need a prefix resolve in Dart scope. This is possible now that
https://dart-review.googlesource.com/c/sdk/+/557680 has rolled into
Flutter.

- 20 library references in `packages/flutter`, `flutter_test`, and
`integration_test`, such as `[widgets]` and `[flutter_test]`.
- `[ui.Rect]`, `[ui.Size]`, and `[flutter_test.expectLater]` in `dev/`.

The generated API docs link these references the same as before.

Towards https://github.com/flutter/flutter/issues/192870 — enabling the
`comment_references` lint.
diff --git a/dev/integration_tests/android_semantics_testing/lib/src/common.dart b/dev/integration_tests/android_semantics_testing/lib/src/common.dart
index cd07cff..3edc88e 100644
--- a/dev/integration_tests/android_semantics_testing/lib/src/common.dart
+++ b/dev/integration_tests/android_semantics_testing/lib/src/common.dart
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/// @docImport 'dart:ui' as ui;
+///
 /// @docImport 'package:flutter/semantics.dart';
 library;
 
diff --git a/dev/tools/android_driver_extensions/lib/native_driver.dart b/dev/tools/android_driver_extensions/lib/native_driver.dart
index 2eb07c0..d1a567f 100644
--- a/dev/tools/android_driver_extensions/lib/native_driver.dart
+++ b/dev/tools/android_driver_extensions/lib/native_driver.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 /// @docImport 'package:flutter_test/flutter_test.dart';
+/// @docImport 'package:flutter_test/flutter_test.dart' as flutter_test;
 library;
 
 import 'dart:async';
diff --git a/packages/flutter/lib/src/foundation/binding.dart b/packages/flutter/lib/src/foundation/binding.dart
index 5e4b7f4..67453c1 100644
--- a/packages/flutter/lib/src/foundation/binding.dart
+++ b/packages/flutter/lib/src/foundation/binding.dart
@@ -5,11 +5,16 @@
 /// @docImport 'dart:convert';
 /// @docImport 'dart:ui';
 ///
+/// @docImport 'package:flutter/foundation.dart' as foundation;
+/// @docImport 'package:flutter/gestures.dart' as gestures;
 /// @docImport 'package:flutter/rendering.dart';
 /// @docImport 'package:flutter/scheduler.dart';
 /// @docImport 'package:flutter/services.dart';
+/// @docImport 'package:flutter/services.dart' as services;
 /// @docImport 'package:flutter/widgets.dart';
+/// @docImport 'package:flutter/widgets.dart' as widgets;
 /// @docImport 'package:flutter_test/flutter_test.dart';
+/// @docImport 'package:flutter_test/flutter_test.dart' as flutter_test;
 library;
 
 import 'dart:async';
diff --git a/packages/flutter/lib/src/painting/image_cache.dart b/packages/flutter/lib/src/painting/image_cache.dart
index 7d55670..9272261 100644
--- a/packages/flutter/lib/src/painting/image_cache.dart
+++ b/packages/flutter/lib/src/painting/image_cache.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/// @docImport 'package:flutter/painting.dart' as painting;
 /// @docImport 'package:flutter/widgets.dart';
 ///
 /// @docImport 'binding.dart';
diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
index 14d2452..aad232d 100644
--- a/packages/flutter/lib/src/rendering/object.dart
+++ b/packages/flutter/lib/src/rendering/object.dart
@@ -5,6 +5,7 @@
 /// @docImport 'dart:ui';
 ///
 /// @docImport 'package:flutter/widgets.dart';
+/// @docImport 'package:flutter/widgets.dart' as widgets;
 ///
 /// @docImport 'box.dart';
 /// @docImport 'paragraph.dart';
diff --git a/packages/flutter/lib/src/widgets/selectable_region.dart b/packages/flutter/lib/src/widgets/selectable_region.dart
index 62c62d2..ed0561a 100644
--- a/packages/flutter/lib/src/widgets/selectable_region.dart
+++ b/packages/flutter/lib/src/widgets/selectable_region.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 /// @docImport 'package:flutter/material.dart';
+/// @docImport 'package:flutter/material.dart' as material;
 /// @docImport 'package:flutter_test/flutter_test.dart';
 ///
 /// @docImport 'editable_text.dart';
diff --git a/packages/flutter_test/lib/src/binding.dart b/packages/flutter_test/lib/src/binding.dart
index eb05d2e..2802299 100644
--- a/packages/flutter_test/lib/src/binding.dart
+++ b/packages/flutter_test/lib/src/binding.dart
@@ -7,6 +7,8 @@
 
 /// @docImport 'dart:io';
 ///
+/// @docImport 'package:flutter_driver/flutter_driver.dart' as flutter_driver;
+///
 /// @docImport 'controller.dart';
 /// @docImport 'test_pointer.dart';
 /// @docImport 'widget_tester.dart';
diff --git a/packages/flutter_test/lib/src/controller.dart b/packages/flutter_test/lib/src/controller.dart
index e7c53f7..ef23f7d 100644
--- a/packages/flutter_test/lib/src/controller.dart
+++ b/packages/flutter_test/lib/src/controller.dart
@@ -6,6 +6,7 @@
 ///
 /// @docImport 'package:flutter/scheduler.dart';
 /// @docImport 'package:flutter_driver/flutter_driver.dart';
+/// @docImport 'package:flutter_test/flutter_test.dart' as flutter_test;
 ///
 /// @docImport 'binding.dart';
 /// @docImport 'finders.dart';
diff --git a/packages/flutter_test/lib/src/goldens.dart b/packages/flutter_test/lib/src/goldens.dart
index 5eb82f8..9b37b60 100644
--- a/packages/flutter_test/lib/src/goldens.dart
+++ b/packages/flutter_test/lib/src/goldens.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 /// @docImport 'package:flutter/widgets.dart';
+/// @docImport 'package:flutter_test/flutter_test.dart' as flutter_test;
 ///
 /// @docImport '_goldens_io.dart';
 /// @docImport 'binding.dart';
diff --git a/packages/flutter_test/lib/src/matchers.dart b/packages/flutter_test/lib/src/matchers.dart
index 9a6f3cd..85bf567 100644
--- a/packages/flutter_test/lib/src/matchers.dart
+++ b/packages/flutter_test/lib/src/matchers.dart
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/// @docImport 'package:flutter_test/flutter_test.dart' as flutter_test;
+///
 /// @docImport '_goldens_io.dart';
 /// @docImport 'window.dart';
 library;
diff --git a/packages/flutter_test/lib/src/test_text_input.dart b/packages/flutter_test/lib/src/test_text_input.dart
index 3516ada..1096290 100644
--- a/packages/flutter_test/lib/src/test_text_input.dart
+++ b/packages/flutter_test/lib/src/test_text_input.dart
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/// @docImport 'package:integration_test/integration_test.dart' as integration_test;
+///
 /// @docImport 'widget_tester.dart';
 library;
 
diff --git a/packages/integration_test/lib/integration_test.dart b/packages/integration_test/lib/integration_test.dart
index 2819c9a..5606eee 100644
--- a/packages/integration_test/lib/integration_test.dart
+++ b/packages/integration_test/lib/integration_test.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 /// @docImport 'package:flutter_driver/flutter_driver.dart';
+/// @docImport 'package:flutter_driver/flutter_driver.dart' as flutter_driver;
 ///
 /// @docImport 'integration_test_driver_extended.dart';
 library;