patch 8.1.0122: translators don't always understand the maintainer message

Problem:    Translators don't always understand the maintainer message.
Solution:   Add a comment that ends up in the generated po file. (Christian
            Brabandt, closes #3037)
diff --git a/src/version.c b/src/version.c
index 5aacf2f..eb119ca 100644
--- a/src/version.c
+++ b/src/version.c
@@ -790,6 +790,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    122,
+/**/
     121,
 /**/
     120,