title: Where should sourceLocale be set in Angular.json?
body: <p>The <a href="https://angular.io/guide/i18n-common-locale-id#set-the-source-locale-id" rel="noreferrer">i18n Angular docs</a> specify that you need to set the language id and locale extension by changing the <code>sourceLocale</code> field in your project's <code>Angular.json</code> file, but this field does not exist in a new project. Where should this field be defined in the json?</p>