make the example config syntactically valid

Author: Rich-Harris

packages/adapter-static/README.md

@@ -12,15 +12,18 @@ import adapter from '@sveltejs/adapter-static';
 
 export default {
 	kit: {
-		// Enable prerendering by default. Remove if using SPA mode
-		prerender.default: true,
 		adapter: adapter({
 			// default options are shown
 			pages: 'build',
 			assets: 'build',
 			fallback: null,
 			precompress: false
-		})
+		}),
+
+		prerender: {
+			// This can be false if you're using a fallback (i.e. SPA mode)
+			default: true
+		}
 	}
 };
 ```