Fix typo in link syntax in about.md

Author: lyoonat

about.md

@@ -7,7 +7,7 @@ permalink: /about/
 
 Text can be **bold**, _italic_, ~~strikethrough~~ or `keyword`.
 
-[Link to another page](/index.html).
+// Link to another page](/index.html).
 
 There should be whitespace between paragraphs.