docs: make properties of objects be linkable

docs/templates/lib/properties.template.html

@@ -2,6 +2,7 @@
 <h2 id="properties">Properties</h2>
 <@- for property in doc.properties @>
 
+<div id="<$ property.name $>"></div>
 * <h3><$ typeList(property.returns.typeList) $> <code><$ property.name $></code></h3>
 
   <$ property.returns.description $>