Small polish to the "missing adapter" error message (#4585)

* improve output server error message

* chore: changeset

Co-authored-by: bholmesdev <hey@bholmes.dev>

.changeset/thick-guests-sell.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Add docs link to "missing adapter" error msg

packages/astro/src/core/build/static-build.ts

@@ -28,9 +28,9 @@ export async function staticBuild(opts: StaticBuildOptions) {
 	if (isModeServerWithNoAdapter(opts.astroConfig)) {
 		throw new Error(`Cannot use \`output: 'server'\` without an adapter.
 Install and configure the appropriate server adapter for your final deployment.
-Example:
+Learn more: https://docs.astro.build/en/guides/server-side-rendering/
 
-  // astro.config.js
+  // Example: astro.config.js
   import netlify from '@astrojs/netlify';
   export default {
     output: 'server',