[docs] Update docs about Cache-Control default headers. (#35336)

* Update docs about Cache-Control default headers.

* Update docs: Override the default in case of gSSP

* Apply suggestions from code review

* Update going-to-production.md

Co-authored-by: Balázs Orbán <info@balazsorban.com>

docs/going-to-production.md

@@ -69,6 +69,12 @@ export async function getServerSideProps({ req, res }) {
 }
 ```
 
+By default, `Cache-Control` headers will be set differently depending on how your page fetches data.
+
+If the page is using `getServerSideProps` or `getInitialProps`, then it will use the default `Cache-Control` header configured by `next start` in order to prevent accidental caching of responses that cannot be cached. If you want a different cache behavior while using SSR you can use `res.setHeader('Cache-Control', 'value_you_prefer')`.
+
+If the page is using `getStaticProps` or automatic static optimization, then it will have s-maxage=REVALIDATE_SECONDS, stale-while-revalidate or if revalidate is not used s-maxage=31536000, stale-while-revalidate.
+
 > **Note:** Your deployment provider must support edge caching for dynamic responses. If you are self-hosting, you will need to add this logic to the edge yourself using a key/value store. If you are using Vercel, [edge caching works without configuration](https://vercel.com/docs/edge-network/caching).
 
 ## Reducing JavaScript Size