patch 9.0.1959: Vim9: methods parameters and types are covariant

Problem:  Vim9: methods parameters and types are covariant
Solution: Support contra-variant type check for object method arguments
          (similar to Dart).

closes: #12965
closes: #13221

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
diff --git a/src/version.c b/src/version.c
index 766333e..e625ea6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1959,
+/**/
     1958,
 /**/
     1957,