Fix documentation links (#1476)

diff --git a/pkgs/test_api/lib/src/frontend/tags.dart b/pkgs/test_api/lib/src/frontend/tags.dart
index 6ad5a22..cb1ea2b 100644
--- a/pkgs/test_api/lib/src/frontend/tags.dart
+++ b/pkgs/test_api/lib/src/frontend/tags.dart
@@ -8,7 +8,7 @@
 ///
 /// See [the documentation on tagging tests][tagging tests].
 ///
-/// [tagging tests]: https://github.com/dart-lang/test/blob/master/README.md#tagging-tests
+/// [tagging tests]: https://github.com/dart-lang/test/blob/master/pkgs/test/README.md#tagging-tests
 @Target({TargetKind.library})
 class Tags {
   /// The tags for the test suite.
diff --git a/pkgs/test_api/lib/test_api.dart b/pkgs/test_api/lib/test_api.dart
index 1857896..7ab4b13 100644
--- a/pkgs/test_api/lib/test_api.dart
+++ b/pkgs/test_api/lib/test_api.dart
@@ -66,7 +66,7 @@
 /// If [retry] is passed, the test will be retried the provided number of times
 /// before being marked as a failure.
 ///
-/// [configuring tags]: https://github.com/dart-lang/test/blob/master/doc/package_config.md#configuring-tags
+/// [configuring tags]: https://github.com/dart-lang/test/blob/master/pkgs/test/doc/configuration.md#configuring-tags
 ///
 /// [onPlatform] allows tests to be configured on a platform-by-platform
 /// basis. It's a map from strings that are parsed as [PlatformSelector]s to
diff --git a/pkgs/test_core/lib/src/runner/plugin/customizable_platform.dart b/pkgs/test_core/lib/src/runner/plugin/customizable_platform.dart
index 065e315..f6d4857 100644
--- a/pkgs/test_core/lib/src/runner/plugin/customizable_platform.dart
+++ b/pkgs/test_core/lib/src/runner/plugin/customizable_platform.dart
@@ -16,8 +16,8 @@
 /// field. The custom settings will be passed to the plugin using
 /// [customizePlatform].
 ///
-/// [override_platforms]: https://github.com/dart-lang/test/blob/master/doc/configuration.md#override_platforms
-/// [define_platforms]: https://github.com/dart-lang/test/blob/master/doc/configuration.md#define_platforms
+/// [override_platforms]: https://github.com/dart-lang/test/blob/master/pkgs/test/doc/configuration.md#override_platforms
+/// [define_platforms]: https://github.com/dart-lang/test/blob/master/pkgs/test/doc/configuration.md#define_platforms
 ///
 /// Plugins that implement this **must** support children of recognized runtimes
 /// (created by [Runtime.extend]) in their [loadChannel] or [load] methods.
diff --git a/pkgs/test_core/lib/test_core.dart b/pkgs/test_core/lib/test_core.dart
index 2dc3185..f0f8625 100644
--- a/pkgs/test_core/lib/test_core.dart
+++ b/pkgs/test_core/lib/test_core.dart
@@ -105,7 +105,7 @@
 /// If [retry] is passed, the test will be retried the provided number of times
 /// before being marked as a failure.
 ///
-/// [configuring tags]: https://github.com/dart-lang/test/blob/master/doc/package_config.md#configuring-tags
+/// [configuring tags]: https://github.com/dart-lang/test/blob/master/pkgs/test/doc/configuration.md#configuring-tags
 ///
 /// [onPlatform] allows tests to be configured on a platform-by-platform
 /// basis. It's a map from strings that are parsed as [PlatformSelector]s to
@@ -183,7 +183,7 @@
 /// [package configuration file][configuring tags]. The parameter can be an
 /// [Iterable] of tag names, or a [String] representing a single tag.
 ///
-/// [configuring tags]: https://github.com/dart-lang/test/blob/master/doc/package_config.md#configuring-tags
+/// [configuring tags]: https://github.com/dart-lang/test/blob/master/pkgs/test/doc/configuration.md#configuring-tags
 ///
 /// [onPlatform] allows groups to be configured on a platform-by-platform
 /// basis. It's a map from strings that are parsed as [PlatformSelector]s to