update SEM-DISNET diagram

SEM-DISNET Documentation/index-en.html

@@ -674,7 +674,7 @@ This ontology has the following classes and properties.</span>
    </div>
 
    <center>
-      <img src="SEM-DISNET_hierarchy.png" alt="General overview of the SEM-DISNET Ontology Class and object properties hierarchy" width="90%"> <figcaption><b>Figure 2</b> - SEM-DISNET hierarchies for Association Classes (A) and Object Properties (B).</figcaption>
+      <img src="SEM-DISNET_hierarchies.png" alt="General overview of the SEM-DISNET Ontology Class and object properties hierarchy" width="90%"> <figcaption><b>Figure 2</b> - SEM-DISNET hierarchies for Association Classes (A) and Object Properties (B).</figcaption>
    </center>