[wip v3]: new i18n, remove _app.mdx, remove newNextLinkBehavior (#2070)

Author: Dimitri POSTOLOV

.changeset/early-walls-hammer.md

@@ -0,0 +1,29 @@
+---
+'nextra': major
+---
+
+- ❌ remove `_app.mdx`, use `_app.{js,jsx}` or `_app.{ts,tsx}` for TypeScript projects instead
+
+- ❌ remove Nextra middleware `nextra/locales`
+
+- ❌ remove `parseFileName` from `nextra/utils`
+
+- ❌ remove `nextra/filter-route-locale`
+
+- ❌ remove `resolvePageMap` and `pageMapCache` from `nextra/page-map`
+
+- ❌ remove `__nextraPageOptions.pageNextRoute`
+
+- ❌ remove `pageOpts.route` and `pageOpts.newNextLinkBehavior`
+
+- ❌ remove `LoaderOptions.defaultLocale`
+
+- ❌ remove `__nextra_internal__.context[route].themeConfig`
+
+- ✅ add `nextra/fetch-filepaths-from-github`
+
+- save `pageMap` to `.next/static/chunks/nextra-page-map-{locale}.mjs`
+
+- save `fileMap` to `.next/static/chunks/nextra-file-map.mjs`
+
+

.eslintrc.cjs

@@ -210,8 +210,8 @@ module.exports = {
     {
       files: [
         'prettier.config.js',
-        'postcss.config.js',
-        'tailwind.config.js',
+        'postcss.config.{js,cjs}',
+        'tailwind.config.{js,cjs}',
         'next.config.js',
         '.eslintrc.cjs'
       ],