patch 8.2.5163: crash when deleting buffers in diff mode

Problem:    Crash when deleting buffers in diff mode.
Solution:   Recompute diffs later.  Skip window without a valid buffer.
diff --git a/src/version.c b/src/version.c
index cf2e77d..c847d59 100644
--- a/src/version.c
+++ b/src/version.c
@@ -736,6 +736,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5163,
+/**/
     5162,
 /**/
     5161,