patch 8.1.1300: in a terminal 'ballooneval' does not work right away

Problem:    In a terminal 'ballooneval' does not work right away.
Solution:   Flush output after drawing the balloon.  Add the <Ignore> key
            code.  Add a test.
diff --git a/src/version.c b/src/version.c
index 1ea47db..7905cda 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1300,
+/**/
     1299,
 /**/
     1298,