Update features.md

Yukaii · Yukaii · commit 01fa05f41c51 · 2019-09-08T00:24:05.000+08:00
Signed-off-by: Yukai Huang &lt;yukaihuangtw@gmail.com&gt;
diff --git a/public/docs/features.md b/public/docs/features.md
@@ -435,6 +435,7 @@ Subscript: H~2~O
 
 ==Marked text==
 
+{ruby base|rubytext}
 
 ### Blockquotes
 
