Article on extension anatomy doesn't mention internationalization files

### MDN URL

https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Anatomy_of_a_WebExtension

### What specific section or headline is this issue about?

_No response_

### What information was incorrect, unhelpful, or incomplete?

There is no mention of the `_locale` folder and its content.

### What did you expect to see?

Inclusion of the `_locale` folder in the diagram, mention in the overview, and a section providing an overview and linked to the [internationalization](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Internationalization) page.

### Do you have any supporting links, references, or citations?

_No response_

### Do you have anything more you want to share?

_No response_