htable: update documentation to reiterate importance of loading DMQ module first if enable_dmq is set

- previously only mentioned in module dependency section

modules/htable/doc/htable_admin.xml

@@ -632,6 +632,11 @@ modparam("htable", "db_expires", 1)
 			repeated on all other nodes. Therefore, it is important to ensure the
 			table definition (size, autoexpire etc.) is identical across all instances.
 		</para>
+		<para>
+		<emphasis>
+			Important: If this parameter is enabled, the DMQ module must be loaded first - otherwise, startup will fail.
+		</emphasis>
+		</para>
 		<para>
 			Currently, values are not replicated on load from DB as it is expected 
 			that in these cases, all servers will load their values from the same DB.