fix link to api documentation

pages/Inner-workings.md

 # Inner workings
 
+Please also refer to the [API documentation](_static/ragdoc/index.html)
+
 ## openHAB synchronization via MQTT
 
 MQTTRoot contains `incomingPrefix`, `outgoingPrefix` and `host` tokens.

pages/contributing.md

 # Contributing
 
-Please also refer to the [API documentation](ragdoc/index.html)
+Please also refer to the [API documentation](_static/ragdoc/index.html)
 
 Steps to create the initial multi-project setup from a single-project setup
 

pages/index.rst

@@ -33,7 +33,7 @@ For contributing, please see `contribution guideline <contributing>`_.
    mqtt.md
    openhab-binding.md
    contributing.md
-   `API documentation <ragdoc/index.html>`_
+   `API documentation <_static/ragdoc/index.html>`_
 
 
 Indices and tables