patch 8.2.1131: Vim9: error message for returning a value is not clear

Problem:    Vim9: error message for returning a value in a function that does
            not return anything is not clear.
Solution:   Add a specific message.
diff --git a/src/version.c b/src/version.c
index c94988f..8f85bb7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1131,
+/**/
     1130,
 /**/
     1129,