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)

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1440,
 /**/
     1439,
 /**/