patch 8.2.0523: loops are repeated

Problem:    Loops are repeated.
Solution:   Use FOR_ALL_ macros. (Yegappan Lakshmanan, closes #5882)
diff --git a/src/gui_w32.c b/src/gui_w32.c
index e6b5dad..5af4105 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -7591,7 +7591,7 @@
     for (col = 0; col < 2; col++)
     {
 	columnWidths[col] = 0;
-	for (pmenu = menu->children; pmenu != NULL; pmenu = pmenu->next)
+	FOR_ALL_CHILD_MENUS(menu, pmenu)
 	{
 	    // Use "dname" here to compute the width of the visible text.
 	    text = (col == 0) ? pmenu->dname : pmenu->actext;