fixed heading for 2.2.1

fixes #55

index.html

@@ -221,8 +221,8 @@ <h5><span data-lang="zh">減少字距</span>
     <h3><span data-lang="zh">中文排版常用字體</span>
   <span data-lang="en">Typefaces for Chinese Characters</span></h3>
     <section id="four_commonly_used_typefaces_for_chinese_composition">
-      <h4 data-lang="zh">中文排版經常使用的四種字體</h4>
-      <h4 data-lang="en">Four Frequently-used Typefaces for Chinese Characters <span class="issue">I'm inclined to think that a heading is superfluous here.</span></h4>
+      <h4><span data-lang="zh">中文排版經常使用的四種字體</span>
+      <span data-lang="en">Four Frequently-used Typefaces for Chinese Characters</h4>
       <p data-lang="zh">中文排版時，主要使用的四種字體為：</p>
       <ul data-lang="zh">
         <li>宋體（明體、明朝體）</li>