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/userfunc.c b/src/userfunc.c
index 0ebd618..6638849 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -1879,7 +1879,7 @@
 	    argp = skipwhite(argp);
 	if (*argp != ',')
 	    break;
-	if (vim9script && !IS_WHITE_OR_NUL(argp[1]))
+	if (vim9script && !IS_WHITE_NL_OR_NUL(argp[1]))
 	{
 	    if (evaluate)
 		semsg(_(e_white_space_required_after_str_str), ",", argp);