docs: add uninstall instructions (#812)

Co-authored-by: Jochum van der Ploeg <[email protected]>
Co-authored-by: Renan <[email protected]>

Author: 3 people

docs/docs/overview.md

@@ -69,6 +69,22 @@ Create a production build which includes a `DockerFile` so that you can deploy a
 dart_frog build
 ```
 
+## Uninstalling 🗑️
+
+To uninstall Dart Frog completely, the [CLI completion](https://github.com/VeryGoodOpenSource/cli_completion) files have to be removed before uninstalling.
+
+```shell
+# 🧹 Uninstalling the Dart Frog CLI completion files
+dart_frog uninstall-completion-files
+```
+
+Now, if you installed Dart Frog globally via Pub, Dart's package manager, you can uninstall Dart Frog using:
+
+```shell
+# 🗑️ Uninstall the Dart Frog CLI from pub.dev
+dart pub global deactivate dart_frog_cli
+```
+
 ## Feature Set ✨
 
 ✅ Hot Reload ⚡️