patch 9.0.0288: when 'cmdheight' is zero some messages are not displayed

Problem:    When 'cmdheight' is zero some messages are not displayed.
Solution:   Use a popup notification window.
diff --git a/src/version.c b/src/version.c
index bfa29ef..b517fe7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -708,6 +708,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    288,
+/**/
     287,
 /**/
     286,