patch 8.2.1504: Vim9: white space checks are only done for a :def function

Problem:    Vim9: white space checks are only done for a :def function.
Solution:   Also do checks at the script level.  Adjust the name of a few
            error messages.
diff --git a/src/list.c b/src/list.c
index c730b1a..e7d288a 100644
--- a/src/list.c
+++ b/src/list.c
@@ -1259,7 +1259,7 @@
 	{
 	    if (vim9script && !IS_WHITE_OR_NUL((*arg)[1]))
 	    {
-		semsg(_(e_white_space_required_after), ",");
+		semsg(_(e_white_space_required_after_str), ",");
 		goto failret;
 	    }
 	    *arg = skipwhite(*arg + 1);
@@ -1276,7 +1276,7 @@
 	    if (do_error)
 	    {
 		if (**arg == ',')
-		    semsg(_(e_no_white_space_allowed_before), ",");
+		    semsg(_(e_no_white_space_allowed_before_str), ",");
 		else
 		    semsg(_("E696: Missing comma in List: %s"), *arg);
 	    }