patch 9.0.1876: Vim9: parsing commands with newlines wrong

Problem:  Vim9: parsing commands with newlines wrong
Solution: Accept a '\n' for parsing lists and command arguments

closes: #13015
closes: #13020

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/list.c b/src/list.c
index 6210fd6..d1494c6 100644
--- a/src/list.c
+++ b/src/list.c
@@ -1592,7 +1592,7 @@
 	had_comma = **arg == ',';
 	if (had_comma)
 	{
-	    if (vim9script && !IS_WHITE_OR_NUL((*arg)[1]) && (*arg)[1] != ']')
+	    if (vim9script && !IS_WHITE_NL_OR_NUL((*arg)[1]) && (*arg)[1] != ']')
 	    {
 		semsg(_(e_white_space_required_after_str_str), ",", *arg);
 		goto failret;