Excerpts and blog lists (mostly)

src/blog/posts/first-post.md

@@ -2,6 +2,13 @@
 title: My first post
 ---
 
+This is an excerpt, written at the start of the post
+
+* Wait, does it not render markdown?
+* Let's find out
+
+---
+
 Something something something
 
 ## Something else