Cleans up trailing whitespace (#700)

_includes/header.html

@@ -36,7 +36,7 @@
       <h2 class="{{ include.type }}-subheading">{{ page.subtitle }}</h2>
       {% endif %}
       {% endif %}
-      
+
       {% if include.type == "post" %}
           <span class="post-meta">Posted on {{ page.date | date: date_format }}</span>
           {% if page.readtime %}
@@ -64,7 +64,7 @@
       <h2 class="{{ include.type }}-subheading">{{ page.subtitle }}</h2>
       {% endif %}
       {% endif %}
-      
+
       {% if include.type == "post" %}
           <span class="post-meta">Posted on {{ page.date | date: date_format }}</span>
           {% if page.readtime %}