patch 8.1.1916: trying to allocate negative amount of memory closing popup

Problem:    Trying to allocate negative amount of memory when closing a popup.
Solution:   Check the rows are not out of bounds.  Don't finish a selection if
            it was never started.
diff --git a/src/version.c b/src/version.c
index 8ece6f1..51851e3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1916,
+/**/
     1915,
 /**/
     1914,