Raise floating windows when their border is clicked (#5196)

This logic already existed for `floating_drag_window`, but we need it
for `floating_resize_window` too.

Fixes #5195.

src/floating.c

@@ -699,6 +699,10 @@ void floating_resize_window(Con *con, const bool proportional,
                             const xcb_button_press_event_t *event) {
     DLOG("floating_resize_window\n");
 
+    /* Push changes before resizing, so that the window gets raised now and not
+     * after the user releases the mouse button */
+    tree_render();
+
     /* corner saves the nearest corner to the original click. It contains
      * a bitmask of the nearest borders (BORDER_LEFT, BORDER_RIGHT, …) */
     border_t corner = 0;