Remove intermediate variable for Rollup

By removing the intermediate variable, we can use one less type
annotation and let the type be inferred instead. This is great, because
the type annotation comes from a dependency we eventually want to get
rid of.

Author: remcohaszing

packages/rollup/lib/index.js

@@ -98,9 +98,7 @@ export function rollup(options) {
       ) {
         const compiled = await formatAwareProcessors.process(file)
         const code = String(compiled.value)
-        /** @type {SourceDescription} */
-        const result = {code, map: compiled.map}
-        return result
+        return {code, map: compiled.map}
       }
     }
   }