patch 9.0.1920: Vim9: cannot write public var in nested object

Problem:  Vim9: cannot write public var in nested object
Solution: Write variable in nested read-only object reference.
          Also test write fails.

closes: #13130
closes: #13131

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Ernie Rael <errael@raelity.com>
diff --git a/src/version.c b/src/version.c
index ec6cce3..5abc4f7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1920,
+/**/
     1919,
 /**/
     1918,