don't show hidden posts in the rss feed

src/blog.rs

@@ -75,7 +75,9 @@ impl Blog {
         );
 
         for p in &self.posts {
-            out.push_str(&p.rss(&self.config.root)?);
+            if !p.hidden {
+                out.push_str(&p.rss(&self.config.root)?);
+            }
         }
 
         out.push_str("</channel></rss>");