patch 9.1.0822: topline might be changed in diff mode unexpectedly

Problem:  topline might be changed in diff mode unexpectedly
          (Jaehwang Jung)
Solution: do not re-calculate topline, when using line() func
          in diff mode.

fixes: #15812
closes: #15950

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 6abc802..74837b3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    822,
+/**/
     821,
 /**/
     820,