Update content_menus README.md references (#2564)

Fix broken references in the README.md.

<img width="1467" alt="image"
src="https://github.com/user-attachments/assets/15f67114-f8a1-4a72-b4a4-0fa375832b26"
/>


## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I have added sample code updates to the [changelog].
- [x] I updated/added relevant documentation (doc comments with `///`).


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

<!-- Links -->
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Style-guide-for-Flutter-repo.md
[CLA]: https://cla.developers.google.com/
[Discord]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Chat.md
[Contributors Guide]:
https://github.com/flutter/samples/blob/main/CONTRIBUTING.md
[changelog]: ../CHANGELOG.md

Author: jonathanmach

context_menus/README.md

@@ -3,7 +3,7 @@
 This sample shows how to create and customize cross-platform context menus,
 such as the text selection toolbar on mobile or the right click menu on desktop.
 
-| ![Cascading example screenshot](https://raw.githubusercontent.com/flutter/samples/main/experimental/context_menus/screenshots/cascading.png) | ![Custom button example screenshot](https://raw.githubusercontent.com/flutter/samples/main/experimental/context_menus/screenshots/custom.png) | ![Email example screenshot](https://raw.githubusercontent.com/flutter/samples/main/experimental/context_menus/screenshots/email.png) | ![Widget example screenshot](https://raw.githubusercontent.com/flutter/samples/main/experimental/context_menus/screenshots/image.png) |
+| ![Cascading example screenshot](https://raw.githubusercontent.com/flutter/samples/main/context_menus/screenshots/cascading.png) | ![Custom button example screenshot](https://raw.githubusercontent.com/flutter/samples/main/context_menus/screenshots/custom.png) | ![Email example screenshot](https://raw.githubusercontent.com/flutter/samples/main/context_menus/screenshots/email.png) | ![Widget example screenshot](https://raw.githubusercontent.com/flutter/samples/main/context_menus/screenshots/image.png) |
 | --- | --- | --- | --- |
 
 ## Running the sample
@@ -12,46 +12,46 @@ Just run `flutter run` in the same directory as this README file.
 
 ## The examples
 
-### [Anywhere](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/anywhere_page.dart)
+### [Anywhere](https://github.com/flutter/samples/blob/main/context_menus/lib/anywhere_page.dart)
 Shows how to create a context menu in the parts of an app that don't related to
 text selection.  For example, a menu in a desktop app that shows when the
 background of the app is right clicked.
 
-### [Cascading menus](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/cascading_menu_page.dart)
+### [Cascading menus](https://github.com/flutter/samples/blob/main/context_menus/lib/cascading_menu_page.dart)
 Shows how to create a context menu with cascading submenus using
 [SubmenuButton](https://master-api.flutter.dev/flutter/material/SubmenuButton-class.html).
 
-### [Custom buttons](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/custom_buttons_page.dart)
+### [Custom buttons](https://github.com/flutter/samples/blob/main/context_menus/lib/custom_buttons_page.dart)
 Shows how to customize the default buttons in the existing context menus.
 
-### [Custom menu](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/custom_menu_page.dart)
+### [Custom menu](https://github.com/flutter/samples/blob/main/context_menus/lib/custom_menu_page.dart)
 Shows how to use any custom widgets as the menu itself, including the option to
 keep the default buttons.
 
-### [Default values](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/default_values_page.dart)
+### [Default values](https://github.com/flutter/samples/blob/main/context_menus/lib/default_values_page.dart)
 Demonstrates how the
 [contextMenuBuilder](https://master-api.flutter.dev/flutter/material/TextField/contextMenuBuilder.html)
 property works with various possible values.
 
-### [Email button](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/email_button_page.dart)
+### [Email button](https://github.com/flutter/samples/blob/main/context_menus/lib/email_button_page.dart)
 Shows how to create an "email" button in the default context menu that shows
 only when an email address is selected.
 
-### [Field types](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/field_types_page.dart)
+### [Field types](https://github.com/flutter/samples/blob/main/context_menus/lib/field_types_page.dart)
 Shows how context menus work in the various different field widgets:
 EditableText, TextField, and CupertinoTextField.
 
-### [Global selection](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/global_selection_page.dart)
+### [Global selection](https://github.com/flutter/samples/blob/main/context_menus/lib/global_selection_page.dart)
 Shows how to create a custom context menu in non-editable selection with
 [SelectionArea](https://master-api.flutter.dev/flutter/material/SelectionArea-class.html).
 
-### [On a widget](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/image_page.dart)
+### [On a widget](https://github.com/flutter/samples/blob/main/context_menus/lib/image_page.dart)
 Shows how to make a widget show a context menu on right click or long press, in
 this case an Image widget.
 
-### [Modified action](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/modified_action_page.dart)
+### [Modified action](https://github.com/flutter/samples/blob/main/context_menus/lib/modified_action_page.dart)
 Shows how to modify an existing button so that a custom action is performed when
 it is tapped.
 
-### [Reordered buttons](https://github.com/flutter/samples/blob/main/experimental/context_menus/lib/reordered_buttons_page.dart)
+### [Reordered buttons](https://github.com/flutter/samples/blob/main/context_menus/lib/reordered_buttons_page.dart)
 Shows how to change the order of the default buttons.