patch 8.1.1527: when moving popup window over the cmdline it is not redrawn

Problem:    When moving a popup window over the command line it is not
            redrawn.
Solution:   Redraw the command line. Move popup redrawing code to the popupwin
            file.
diff --git a/src/proto/screen.pro b/src/proto/screen.pro
index ab73e0b..0aaed5f 100644
--- a/src/proto/screen.pro
+++ b/src/proto/screen.pro
@@ -16,6 +16,7 @@
 int conceal_cursor_line(win_T *wp);
 void conceal_check_cursor_line(void);
 void update_debug_sign(buf_T *buf, linenr_T lnum);
+int get_wcr_attr(win_T *wp);
 void updateWindow(win_T *wp);
 int screen_get_current_line_off(void);
 void screen_line(int row, int coloff, int endcol, int clear_width, int flags);