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/evalvars.c b/src/evalvars.c
index 335f850..fbf521e 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -811,7 +811,7 @@
 						   || !IS_WHITE_OR_NUL(*expr)))
 	    {
 		vim_strncpy(op, expr - len, len);
-		semsg(_(e_white_space_required_before_and_after), op);
+		semsg(_(e_white_space_required_before_and_after_str), op);
 		i = FAIL;
 	    }