patch 9.1.1162: completion popup not cleared in cmdline

Problem:  When an info popup spans into the cmdline area and ESC is
          pressed, some content remains visible on screen (yu3s)
Solution: Add popup_overlays_cmdline() check in screen_fill() to prevent
          prematurely clearing the clear_cmdline flag (glepnir).

fixes: #15627
closes: #16765

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/popupwin.c

@@ -40,6 +40,8 @@ static int  message_win_time = 3000;
 // hit-enter prompt.
 static int    start_message_win_timer = FALSE;
 
+static int popup_on_cmdline = FALSE;
+
 static void may_start_message_win_timer(win_T *wp);
 #endif
 
@@ -4564,7 +4566,19 @@ popup_hide_info(void)
     win_T *wp = popup_find_info_window();
 
     if (wp != NULL)
+    {
+	popup_on_cmdline = wp->w_popup_flags & POPF_ON_CMDLINE;
 	popup_hide(wp);
+    }
+}
+
+/*
+ * Returns TRUE if a popup extends into the cmdline area.
+ */
+    int
+popup_overlaps_cmdline(void)
+{
+    return popup_on_cmdline;
 }
 
 /*