docs: More on codecs

Author: amannn

docs/src/pages/docs/usage/extraction.mdx

@@ -379,7 +379,7 @@ const withNextIntl = createNextIntlPlugin({
 });
 ```
 
-See also the built-in [`codecs`](https://github.com/amannn/next-intl/tree/main/packages/next-intl/src/extractor/format/codecs) for inspiration.
+See also the built-in [`codecs`](https://github.com/amannn/next-intl/tree/main/packages/next-intl/src/extractor/format/codecs) for inspiration, as well as the supplied types and JSDoc reference.
 
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