feat(i18n): standardize bilingual catalogs and tooling

packages/lexical/src/root.tsx

@@ -16,7 +16,7 @@ import {
   findLexicalActions,
 } from "./action-declarations"
 import { LexicalActionsProvider } from "./actions-context"
-import { messages as englishMessages } from "./locales/en"
+import { messages as englishMessages } from "./locales/en-US"
 
 const pluginKeys = new WeakMap<ComponentType, string>()
 let nextPluginKey = 0
@@ -46,7 +46,7 @@ function LexicalI18nBoundary({ children }: { children: ReactNode }) {
   if (hasI18nProvider) return children
 
   return (
-    <I18nProvider catalogs={{ en: englishMessages }} locale="en">
+    <I18nProvider catalogs={{ "en-US": englishMessages }} locale="en-US">
       {children}
     </I18nProvider>
   )