patch 9.1.0643: terminal: cursor may end up on invalid position

Problem:  terminal: cursor may end up on invalid position after reducing
          the scrollback lines (user202729)
Solution: After reducing the scrollback size, check the cursor position,
          making sure it does not end up on an invalid line

fixes: #15351

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 1536859..bfcb7bf 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    643,
+/**/
     642,
 /**/
     641,