patch 8.0.1612: need to close terminal after shell stopped

Problem:    Need to close terminal after shell stopped.
Solution:   Make :terminal without argument close the window by default.
diff --git a/src/version.c b/src/version.c
index 6ab5963..a588344 100644
--- a/src/version.c
+++ b/src/version.c
@@ -767,6 +767,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1612,
+/**/
     1611,
 /**/
     1610,