patch 8.2.1840: Vim9: error message is not clear about compilation error

Problem:    Vim9: error message is not clear about compilation error.
Solution:   Say "compiling" instead of "processing".
diff --git a/src/version.c b/src/version.c
index f972cbd..2b3657b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1840,
+/**/
     1839,
 /**/
     1838,