patch 8.2.2983: Vim9: an inline function requires specifying the return type

Problem:    Vim9: an inline function requires specifying the return type.
Solution:   Make the return type optional.
diff --git a/src/version.c b/src/version.c
index 17ae9a4..fcb0d92 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2983,
+/**/
     2982,
 /**/
     2981,