docs(angular): add translation files content (#6947)

src/data/roadmaps/angular/content/translation-files@jL5amGV1BAX_V5cyTIH7d.md

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 # Translation Files
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+After you prepare a component for translation, use the `extract-i18n` Angular CLI command to extract the marked text in the component into a source language file. The marked text includes text marked with `i18n`, attributes marked with `i18n`-attribute, and text tagged with `$localize`. The `extract-i18n` command creates a source language file named `messages.xlf` in the root directory of your project.  If you have multiple language files, add the locale to the file name, like `messages.{locale}.xlf`.
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+Visit the following resources to learn more:
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+- [@official@Angular Official Docs - Translation Files](https://angular.dev/guide/i18n/translation-files)
+- [@official@Angular Official Docs - Extract i18n](https://angular.dev/cli/extract-i18n)
+- [@article@Angular i18n: internationalization & localization with examples](https://lokalise.com/blog/angular-i18n/)