Update docs.

Author: yarrow.love

docs/content/4.api/3.configuration.md

@@ -411,6 +411,13 @@ Toggles the document-driven mode.
 | `injectPage`      |      `boolean`      | Inject `[...slug].vue` pre-configured page                     |
 | `trailingSlash`   |      `boolean`      | Add a slash at the end of  `canonical` and `og:url`            |
 
+## `useCache`
+
+- Type: `boolean`
+- Default: `true`
+
+When `true`, the production server (`nuxt start`) will use cached version of the content (generated after running `nuxt build`) instead of parsing files. This improves app startup time, but makes app unaware of any content changes.
+
 ## `respectPathCase`
 
 - Type: `boolean`{lang=ts}