patch 9.0.0639: checking for popup in screen_char() is too late

Problem:    Checking for popup in screen_char() is too late, the attribute has
            already been changed.
Solution:   Move check for popup to where screen_char() is called.
diff --git a/src/version.c b/src/version.c
index dd80828..e998716 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    639,
+/**/
     638,
 /**/
     637,