Update modules/ROOT/nav.adoc

Author: kemister85

modules/ROOT/nav.adoc

@@ -417,7 +417,7 @@
 ** xref:release-notes.adoc[Release notes for {productname}]
 *** {productname} 8.1.0
 **** xref:8.1.0-release-notes.adoc#overview[Overview]
-**** xref:8.1.0-release-notes.adoc#new-premium-plugins[New Premium plugins]
+**** xref:8.1.0-release-notes.adoc#new-premium-plugin[New Premium plugin]
 **** xref:8.1.0-release-notes.adoc#accompanying-premium-plugin-changes[Accompanying Premium plugin changes]
 **** xref:8.1.0-release-notes.adoc#improvements[Improvements]
 **** xref:8.1.0-release-notes.adoc#changes[Changes]