patch 9.0.0592: display not cleared when scrolling back in messages

Problem:    Display not cleared when scrolling back in messages, a background
            color is set and t_ut is empty.
Solution:   Clear to the end of the display if needed. (closes #8973)
diff --git a/src/version.c b/src/version.c
index d17276b..ab4cea3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    592,
+/**/
     591,
 /**/
     590,