patch 8.0.1440: terminal window: some vterm responses are delayed

Problem:    Terminal window: some vterm responses are delayed.
Solution:   After writing input. check if there is output to read. (Ozaki
            Kiichi, closes #2594)
diff --git a/src/version.c b/src/version.c
index 09fb300..282f662 100644
--- a/src/version.c
+++ b/src/version.c
@@ -772,6 +772,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1440,
+/**/
     1439,
 /**/
     1438,