diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index bb6f917..b7791cc 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -1311,7 +1311,7 @@
 				encoding.  The value is a |String|.  See
 				|encoding-names| for the supported values
 				(plus the special value "none").
-							*E1515*
+							*E1515* *E1516*
 		When current 'encoding' is "utf-8", an error is given and an
 		empty List is returned if an invalid byte sequence is
 		encountered in {blob}.  To suppress this validation and get