docs: add note on Aside src

Author: bholmesdev

examples/with-markdoc/src/components/Aside.astro

@@ -1,4 +1,7 @@
 ---
+// Inspired by the `Aside` component from docs.astro.build
+// https://github.com/withastro/docs/blob/main/src/components/Aside.astro
+
 export interface Props {
 	type?: 'note' | 'tip' | 'caution' | 'danger';
 	title?: string;