Update runtime files
diff --git a/runtime/doc/testing.txt b/runtime/doc/testing.txt
index 2811568..fb43fbc 100644
--- a/runtime/doc/testing.txt
+++ b/runtime/doc/testing.txt
@@ -1,4 +1,4 @@
-*testing.txt* For Vim version 8.2. Last change: 2022 Jan 13
+*testing.txt* For Vim version 8.2. Last change: 2022 Jan 20
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -352,7 +352,7 @@
Run {cmd} and add an error message to |v:errors| if it does
NOT produce an error or when {error} is not found in the
error message. Also see |assert-return|.
-
+ *E856*
When {error} is a string it must be found literally in the
first reported error. Most often this will be the error code,
including the colon, e.g. "E123:". >