sort all non-md files at the end in nav

src/main.rs

@@ -283,6 +283,19 @@ fn update_garden<P: AsRef<Path>>(
         })
         .collect();
     files.sort();
+    files.sort_by_key(|p| {
+        println!("{:?}", p);
+        match p.extension() {
+            None => -1,
+            Some(ext) => {
+                if ext == "md" {
+                    0
+                } else {
+                    1
+                }
+            }
+        }
+    });
 
     if files.is_empty() {
         return Err(anyhow!("Garden is empty."));