Add disclaimer

Author: Kate Jeffreys

docs/_includes/article.html

@@ -3,6 +3,8 @@
 
 <h1><a href="{{site.baseurl}}{{topic.url}}">{{topic.title}}</a></h1>
 
+<div class="disclaimer">This documentation is a work in progress. It describes prerelease software, and is subject to change.</div>
+
 {% if page.addsectiontoc %}
 {% include sectiontoc.html %}
 {% endif %}

docs/css/main.css

@@ -243,6 +243,15 @@ article {
   min-width: 1px;
 }
 
+.disclaimer {
+  border: 1px solid blue;
+  margin: 20px 20px;
+  padding: 6px;
+  border-radius: 4px;
+  color: #666;
+  background-color: #eee;
+}
+
 .prevnext {
   display: flex;
   justify-content: space-between;