Update headings and add design section in ascii-tools

Author: benelog

content/ascii-tools.md

@@ -1,11 +1,14 @@
 - <https://asciinema.org/>
 
-# Editor
+## Design
+- https://tui.studio/
+- 
+## Editor
 
 - <https://textik.com>
 - <http://asciiflow.com/>
 
-# UI framework
+## UI framework
 
 - Ascii로 그래프 같은 출력물 만들어줌
   - <https://github.com/mdr/ascii-graphs>