Fixes the case when using a completely custom theme, importing anything
from vitepress causes the entire default theme to be imported too.
BREAKING CHANGE: the default theme is now exposed via 'vitepress/theme',
instead of a named export from 'vitepress'.
BREAKING CHANGE: `$theme` global computed is renamed to `$themeConfig`
to align better with VuePress.
Co-authored-by: Kia King Ishii <kia.king.08@gmail.com>
* feat: set language selector on navbar
* feat: hide language selector if no other langages contents
* feat: i18n selectText
* fix: move language selector before repo link
* fix: change reference of locales
* fix: fix not to fail when no locales