patch 9.1.1223: wrong translation used for encoding failures

Problem:  wrong translation for encoding failures because of using
          literal "from" and "to" in the resulting error message
          (RestorerZ)
Solution: use separate error messages for errors "from" and "to"
          encoding errors.

fixes: #16898
closes: #16918

Signed-off-by: Christian Brabandt <cb@256bit.org>
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
diff --git a/runtime/doc/tags b/runtime/doc/tags
index c25effa..8f3fd50 100644
--- a/runtime/doc/tags
+++ b/runtime/doc/tags
@@ -4589,6 +4589,7 @@
 E1513	message.txt	/*E1513*
 E1514	options.txt	/*E1514*
 E1515	builtin.txt	/*E1515*
+E1516	builtin.txt	/*E1516*
 E152	helphelp.txt	/*E152*
 E153	helphelp.txt	/*E153*
 E154	helphelp.txt	/*E154*