auto-close elements with no child

src/element.rs

@@ -38,6 +38,10 @@ impl fmt::Debug for Element {
         for attr in &self.attributes {
             write!(fmt, " {}", attr)?;
         }
+        if self.children.is_empty() {
+            write!(fmt, "/>")?;
+        }
+        else {
             write!(fmt, ">")?;
             for child in &self.children {
                 match *child {
@@ -50,6 +54,7 @@ impl fmt::Debug for Element {
                 }
             }
             write!(fmt, "</{}>", self.name)?;
+        }
         Ok(())
     }
 }