Add meta to form

docs/documentation/form/checkbox.html

@@ -34,6 +34,12 @@ doc-subtab: checkbox
     <h2 class="subtitle">
       The 2-state <strong>checkbox</strong> in its native format
     </h2>
+    {%
+      include meta.html
+      colors=false
+      sizes=false
+      variables=false
+    %}
 
     <hr>