Update README.md
Implemented in https://github.com/dart-lang/sdk/issues/56186
Credits @srawlins
diff --git a/README.md b/README.md
index b49dee1..f3901ce 100644
--- a/README.md
+++ b/README.md
@@ -288,6 +288,24 @@
packages, especially if different command lines are used for dartdoc. It is recommended to use collision-resistant
naming for any macros by including the package name and/or library it is defined in within the name.
+### Documentation imports (`/// @docImport`)
+
+Libraries that are only referenced in documentation comments (`[Future]`) can be imported with a
+`/// @docImport '<uri>'` comment on the `library` element, like:
+
+```dart
+/// @docImport 'dart:async';
+/// @docImport 'package:flutter/element.dart' show Element;
+/// @docImport '../path/to/somwhere.dart';
+/// @docImport 'dart:html' as 'html';
+library;
+
+/// We can now reference [Future] from dart:async, [Element] from Flutter's element library,
+/// and [html.Element] from dart:html, even if none of these libraries are actually imported
+/// by this library.
+class Foo {}
+```
+
### Tools
Dartdoc allows you to filter parts of the documentation through an external tool
