docs: Add note that Server Actions work with static routes (#55626)

In the new next.js v13.5 blog post, the [other improvements section](https://nextjs.org/blog/next-13-5#other-improvements) mentions:

> [Improvement] Server Actions now work with fully static routes (including revalidating data with ISR)

In the forms and mutation docs page, the [good to know section](https://nextjs.org/docs/app/building-your-application/data-fetching/forms-and-mutations#how-server-actions-work) mentions:

> Currently, if a route uses a Server Action, it is required to [render dynamically](https://nextjs.org/docs/app/building-your-application/rendering/server-components#server-rendering-strategies).

I have changed the good to know section to convey the new improvement mentioned in the v13.5 blog post

docs/02-app/01-building-your-application/02-data-fetching/03-forms-and-mutations.mdx

@@ -43,6 +43,7 @@ module.exports = {
 > - Forms calling Server Actions from Server Components can function without JavaScript.
 > - Forms calling Server Actions from Client Components will queue submissions if JavaScript isn't loaded yet, prioritizing client hydration.
 > - Server Actions inherit the [runtime](/docs/app/building-your-application/rendering/edge-and-nodejs-runtimes) from the page or layout they are used on.
+> - Server Actions work with fully static routes (including revalidating data with ISR).
 
 ## Revalidating Cached Data