Update postgres.md

'Annotations' is a plural noun, so it doesn't require adding ‑s to the end of the verb

docs/sources/features/datasources/postgres.md

@@ -186,7 +186,7 @@ ORDER BY atimestamp ASC
 
 ## Annotations
 
-[Annotations]({{< relref "reference/annotations.md" >}}) allows you to overlay rich event information on top of graphs. You add annotation queries via the Dashboard menu / Annotations view.
+[Annotations]({{< relref "reference/annotations.md" >}}) allow you to overlay rich event information on top of graphs. You add annotation queries via the Dashboard menu / Annotations view.
 
 An example query: