[Fix] Add --[no-]shrink instruction for release builds (#11022)

Add --[no-]shrink instruction for release builds.

Fixes: #10032

## Presubmit checklist

- [x] This PR is marked as draft with an explanation if not meant to
land until a future stable release.
- [x] This PR doesn’t contain automatically generated corrections
(Grammarly or similar).
- [x] This PR follows the [Google Developer Documentation Style
Guidelines](https://developers.google.com/style) — for example, it
doesn’t use _i.e._ or _e.g._, and it avoids _I_ and _we_ (first person).
- [x] This PR uses [semantic line
breaks](https://github.com/dart-lang/site-shared/blob/main/doc/writing-for-dart-and-flutter-websites.md#semantic-line-breaks)
of 80 characters or fewer.

---------

Co-authored-by: Shams Zakhour (ignore Sfshaza) <[email protected]>

src/content/deployment/android.md

@@ -249,6 +249,10 @@ To disable R8, pass the `--no-shrink` flag to
 :::note
 Obfuscation and minification can considerably extend compile time
 of the Android application.
+
+The `--[no-]shrink` flag has no effect. Code shrinking is always enabled in release builds.
+To learn more, check out
+[Shrink, obfuscate, and optimize your app]({{site.android-dev}}/studio/build/shrink-code).
 :::
 
 ## Enable multidex support