Increase search input maxlength

Closes #313.

views/app.erb

@@ -3,7 +3,7 @@
     <a class="_home-link"></a>
     <a class="_menu-link"></a>
     <form class="_search">
-      <input type="search" class="_search-input" placeholder="Search&hellip;" autocomplete="off" autocapitalize="off" autocorrect="off" spellcheck="false" maxlength="20">
+      <input type="search" class="_search-input" placeholder="Search&hellip;" autocomplete="off" autocapitalize="off" autocorrect="off" spellcheck="false" maxlength="30">
       <a class="_search-clear"></a>
       <div class="_search-tag"></div>
     </form>