Implemented the "Improve this page" feature. #3495

Created an "Improve this page" link for all the documentation headers. The
feature uses the fa-pencil icon of font awesome. Improvement over #3504(closed).

See issue #3495 for more information.

Signed-off-by: Martin Jorn Rogalla <martin@martinrogalla.com>

site/_layouts/docs.html

@@ -9,6 +9,9 @@ layout: default
 
       <div class="unit four-fifths">
         <article>
+          <div class="improve right">
+            <a href="https://github.com/jekyll/jekyll/edit/master/site/{{ page.path }}">Improve this page <i class="fa fa-pencil"></i></a>
+          </div>
           <h1>{{ page.title }}</h1>
           {{ content }}
           {% include section_nav.html %}

site/_sass/_font-awesome.scss

@@ -20,3 +20,6 @@
 .fa-link:before {
   content: "\f0c1";
 }
+.fa-pencil:before {
+  content: "\f040";
+}

site/_sass/_style.scss

@@ -528,6 +528,12 @@ aside {
   }
 }
 
+.improve {
+  margin-top: 0;
+  padding: 25px 0 0;
+  font-size: 16px;
+}
+
 .docs-nav-mobile select {
   color: #000;
   width: 100%;