patch 9.1.1325: tests: not checking error numbers properly

Problem:  tests: not checking error numbers properly.
Solution: Add a trailing comma to avoid matching a different error
          number with the same prefix (zeertzjq)

closes: #17159

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_listdict.vim b/src/testdir/test_listdict.vim
index fb350a8..a7e9cb7 100644
--- a/src/testdir/test_listdict.vim
+++ b/src/testdir/test_listdict.vim
@@ -1412,7 +1412,7 @@
   call v9.CheckLegacyAndVim9Failure(['VAR d = {"k": 10}', 'echo d[1 : 2]'], 'E719:')
 
   call assert_fails("let v = [4, 6][{-> 1}]", 'E729:')
-  call v9.CheckDefAndScriptFailure(['var v = [4, 6][() => 1]'], ['E1012', 'E703:'])
+  call v9.CheckDefAndScriptFailure(['var v = [4, 6][() => 1]'], ['E1012:', 'E703:'])
 
   call v9.CheckLegacyAndVim9Failure(['VAR v = range(5)[2 : []]'], ['E730:', 'E1012:', 'E730:'])