Generalize documentation helpers

Change-Id: Iaba69a433f25d2160857694b0b434c51c02c0367
diff --git a/templates/doc/api.html.ep b/templates/doc/api.html.ep
index df5bcea..6aad5cb 100644
--- a/templates/doc/api.html.ep
+++ b/templates/doc/api.html.ep
@@ -1,9 +1,9 @@
 % layout 'main', title => 'KorAP: Application Programming Interface';
 
-<h2 id="tutorial-top">Application Programming Interface</h2>
+%= page_title
 
 <p>Internally the communication between KorAP components is done using the KoralQuery protocol.
-  The specification for KoralQuery is available on <%= doc_ext_link_to 'GitHub', "http://korap.github.io/Koral" %>.
+  The specification for KoralQuery is available on <%= ext_link_to 'GitHub', "http://korap.github.io/Koral" %>.
   All API endpoints either use KoralQuery or are (more or lest) REST-ful web APIs.</p>
 
-<p>All publicly available API endpoints including their requests and responses are described in the <%= doc_ext_link_to 'GitHub Wiki', "https://github.com/KorAP/Kustvakt/wiki" %> of <%= doc_link_to 'Kustvakt', 'korap', 'kustvakt' %>.</p>
+<p>All publicly available API endpoints including their requests and responses are described in the <%= ext_link_to 'GitHub Wiki', "https://github.com/KorAP/Kustvakt/wiki" %> of <%= embedded_link_to 'Kustvakt', 'korap', 'kustvakt' %>.</p>