fix: multiple markdown tokens in header text (#564)

Author: halaaro

lib/util/parseHeaders.js

@@ -13,9 +13,9 @@ const unescapeHtml = html => String(html)
   .replace(/>/g, '>')
 
 const removeMarkdownToken = str => String(str)
-  .replace(/\[(.*)\]\(.*\)/, '$1')            // []()
-  .replace(/(`|\*\*|\*|_)(.*[^\\])\1/, '$2')  // `{t}` | *{t}* | **{t}** | _{t}_
-  .replace(/(\\)(\*|_|`)/g, '$2')             // remove escape char '\'
+  .replace(/\[(.*)\]\(.*\)/, '$1')              // []()
+  .replace(/(`|\*{1,3}|_)(.*?[^\\])\1/g, '$2')  // `{t}` | *{t}* | **{t}** | ***{t}*** | _{t}_
+  .replace(/(\\)(\*|_|`)/g, '$2')               // remove escape char '\'
 
 exports.removeTailHtml = (str) => {
   return String(str).replace(/<.*>\s*$/g, '')