Replace "server-generated" by "database-generated" in readOnly example paragraph

Author: dlax

jsonschema-validation.xml

@@ -751,7 +751,7 @@
                     rejected by that owning authority.
                 </t>
                 <t>
-                    For example, this property would be used to mark a server-generated serial
+                    For example, this property would be used to mark a database-generated serial
                     number as read-only.
                 </t>
                 <t>