Update ontology-documentation.md

_docs/ontology-documentation.md

@@ -67,7 +67,7 @@ Alternative words or phrases closely related in meaning to the term name, with i
 Custom synonym types are also used in the ontology. For example, a number of synonyms are designated as systematic synonyms; synonyms of this type are exact synonyms of the term name.
 
 ### Database cross-references
-Database cross-references, or dbxrefs, refer to identical or very similar objects in other databases. For instance, the molecular function term *[cytosine deaminase activity](http://amigo.geneontology.org/amigo/term/GO:0004131)*{:target="blank"} is cross-referenced to [RHEA:20605](https://www.rhea-db.org/reaction.xhtml?id=20605){:target="blank"}; the biological process term [sulfate assimilation](http://amigo.geneontology.org/amigo/term/GO:0000103){:target="blank"} has the [InterPro](https://www.ebi.ac.uk/interpro/){:target="blank"} cross-reference [Sulphate adenylyltransferase (IPR002650)](https://www.ebi.ac.uk/interpro/entry/IPR002650){:target="blank"}.
+Database cross-references, or dbxrefs, refer to identical or very similar objects in other databases. For instance, the molecular function term *[cytosine deaminase activity](http://amigo.geneontology.org/amigo/term/GO:0004131)*{:target="blank"} is cross-referenced to [RHEA:20605](https://www.rhea-db.org/reaction.xhtml?id=20605){:target="blank"}; the biological process term [sulfate assimilation](http://amigo.geneontology.org/amigo/term/GO:0000103){:target="blank"} has the [InterPro](https://www.ebi.ac.uk/interpro/){:target="blank"} cross-reference [Sulphate adenylyltransferase (IPR002650)](https://www.ebi.ac.uk/interpro/entry/IPR002650){:target="blank"}. See [GO cross-references documentation](/docs/download-mappings.md) for the full list of cross-referenced databases.
 
 ### Comment
 Any extra information about the term and its usage.