patch 8.2.3934: repeating line comment is undesired for "O" command

Problem:    Repeating line comment is undesired for "O" command.
Solution:   Do not copy line comment leader for "O". (closes #9426)
diff --git a/src/change.c b/src/change.c
index 1e008a4..bc77fa2 100644
--- a/src/change.c
+++ b/src/change.c
@@ -1655,13 +1655,14 @@
 	lead_len = get_leader_len(saved_line, &lead_flags,
 							dir == BACKWARD, TRUE);
 #ifdef FEAT_CINDENT
-	if (lead_len == 0 && do_cindent)
+	if (lead_len == 0 && do_cindent && dir == FORWARD)
 	{
+	    // Check for a line comment after code.
 	    comment_start = check_linecomment(saved_line);
 	    if (comment_start != MAXCOL)
 	    {
 		lead_len = get_leader_len(saved_line + comment_start,
-					   &lead_flags, dir == BACKWARD, TRUE);
+						     &lead_flags, FALSE, TRUE);
 		if (lead_len != 0)
 		{
 		    lead_len += comment_start;