Automatically add links to API-docs in examples

When we create the examples, we know exactly which specific `ol.…` symbols
we `goog.require(…)`. We can create links to the API documentation of these
symbols automatically.

config/examples/example.html

@@ -33,6 +33,7 @@
           <p id="shortdesc">{{ shortdesc }}</p>
           <div id="docs">{{ md docs }}</div>
           <div id="tags">{{ tags }}</div>
+          <div id="api-links">Related API documentation: {{{ js.apiHtml }}}</div>
         </div>
       </div>