Update README.md (#140382)

Update the "fast results" subsection of readme with recent developments.

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#overview
[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[test-exempt]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes
[Discord]: https://github.com/flutter/flutter/wiki/Chat

---------
Co-authored-by: Parker Lougheed <parlough@gmail.com>

README.md

@@ -65,12 +65,15 @@ support for customizing or creating entirely new visual components.
 
 ### Fast results
 
-Flutter is fast. It's powered by the same hardware-accelerated 2D graphics
-library that underpins Chrome and Android: [Skia]. We architected Flutter to
+Flutter is fast. It's powered by hardware-accelerated 2D graphics
+libraries like [Skia] (that underpins Chrome and Android) and
+[Impeller]. We architected Flutter to
 support glitch-free, jank-free graphics at the native speed of your device.
+
 Flutter code is powered by the world-class [Dart platform], which enables
-compilation to 32-bit and 64-bit ARM machine code for iOS and Android, as well
-as JavaScript for the web and Intel x64 for desktop devices.
+compilation to 32-bit and 64-bit ARM machine code for iOS and Android,
+JavaScript and WebAssembly for the web, as well as Intel x64 and ARM
+for desktop devices.
 
 <p align="center"><img src="https://github.com/flutter/website/blob/main/src/assets/images/docs/homepage/dart-diagram-small.png?raw=true" alt="Dart diagram"></p>
 
@@ -118,3 +121,4 @@ Information on how to get started can be found in our
 [Windows FFI]: https://docs.flutter.dev/development/platform-integration/windows/building#integrating-with-windows
 [platform channels]: https://docs.flutter.dev/development/platform-integration/platform-channels
 [interop example]: https://github.com/flutter/flutter/tree/master/examples/platform_channel
+[Impeller]: https://docs.flutter.dev/perf/impeller