Address Ameba issue

src/spectator/node_iterator.cr

@@ -18,10 +18,9 @@ module Spectator
     # Retrieves the next `Node`.
     # If there are none left, then `Iterator::Stop` is returned.
     def next
-      # Keep going until either:
-      # a. a node is found.
-      # b. the stack is empty.
-      until @stack.empty?
+      # Nothing left to iterate.
+      return stop if @stack.empty?
+
       # Retrieve the next node.
       node = @stack.pop
 
@@ -32,11 +31,7 @@ module Spectator
       end
 
       # Return the current node.
-        return node
-      end
-
-      # Nothing left to iterate.
-      stop
+      node
     end
 
     # Restart the iterator at the beginning.