patch 8.1.0089: error when ending the terminal debugger

Problem:    error when ending the terminal debugger
Solution:   Fix deleting defined signs for breakpoints.  Make the debugger
            work better on MS-Windows.
diff --git a/src/version.c b/src/version.c
index 9a1fbc6..d49516e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    89,
+/**/
     88,
 /**/
     87,