patch 8.2.2396: Vim9: no white space allowed before "->"

Problem:    Vim9: no white space allowed before "->".
Solution:   Allow for white space. (closes #7725)
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 9562e6b..b9ae13d 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -3313,8 +3313,9 @@
 	if (vim_strchr((char_u *)"{('[\"@", *p) != NULL
 	       || ((p = to_name_const_end(pskip)) > eap->cmd && *p != NUL))
 	{
-	    int oplen;
-	    int heredoc;
+	    int	    oplen;
+	    int	    heredoc;
+	    char_u  *swp = skipwhite(p);
 
 	    if (
 		// "(..." is an expression.
@@ -3332,7 +3333,7 @@
 			 || eap->cmd[1] == ':'
 			    )
 			    // "varname->func()" is an expression.
-			: (*p == '-' && p[1] == '>')))
+			: (*swp == '-' && swp[1] == '>')))
 	    {
 		if (*eap->cmd == '{' && ends_excmd(*skipwhite(eap->cmd + 1)))
 		{