chore: make Rehydratable use Awaitable; add docblock

src/service/Routing.ts

@@ -73,6 +73,14 @@ export class Routing extends Unit {
         return this.compiledRoutes
     }
 
+    /**
+     * Resolve a UniversalPath to a file served as an asset.
+     * @example
+     * ```ts
+     * this.getAssetPath('images', '123.jpg').toRemote  // => http://localhost:8000/assets/images/123.jpg
+     * ```
+     * @param parts
+     */
     public getAssetPath(...parts: string[]): UniversalPath {
         return this.getAssetBase().concat(...parts)
     }