patch 9.0.1989: Vim9: double error message given

Problem:  Vim9: double error message given
Solution: Only give second error message, if ther
          wasn't one given before

closes: #13278

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 02dd9bf..64c68d9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1989,
+/**/
     1988,
 /**/
     1987,