patch 9.1.1294: gui tabline menu does not use confirm when closing tabs

Problem:  gui tabline menu does not use confirm when closing tabs
Solution: use ":confirm tabclose" explicitly (JMcKiern)

closes: #17093

Signed-off-by: JMcKiern <jmckiern@tcd.ie>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/normal.c b/src/normal.c
index e7915d6..6cd9004 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -3074,10 +3074,10 @@
     {
 	case TABLINE_MENU_CLOSE:
 	    if (current_tab == 0)
-		do_cmdline_cmd((char_u *)"tabclose");
+		do_cmdline_cmd((char_u *)"confirm tabclose");
 	    else
 	    {
-		vim_snprintf((char *)IObuff, IOSIZE, "tabclose %d",
+		vim_snprintf((char *)IObuff, IOSIZE, "confirm tabclose %d",
 								 current_tab);
 		do_cmdline_cmd(IObuff);
 	    }