docs: Further tweak to default-theme-config.md

docs/reference/default-theme-config.md

@@ -1,6 +1,6 @@
 # Default Theme Config
 
-Theme config lets you customize your theme. You can define theme config via the `themeConfig` option inside `.vitepress/config.ts`:
+Theme config lets you customize your theme. You can define theme config via the `themeConfig` option inside [`.vitepress/config.[extension]`](./site-config):
 
 ```ts
 export default {
@@ -17,7 +17,7 @@ export default {
 }
 ```
 
-**The options documented on this page only apply to the default theme.** Different themes expect different theme config. When using a custom theme, the theme config object will be passed to the theme so the theme can define conditional behavior based on it.
+**The options documented on this page only apply to the default theme.** Different themes expect different theme configuration options. When using a custom theme, the theme config object will be passed to the theme so the theme can define conditional behavior based on it.
 
 ## i18nRouting