patch 8.1.1815: duplicating info for internal functions

Problem:    Duplicating info for internal functions.
Solution:   Use one table to list internal functions.
diff --git a/src/version.c b/src/version.c
index b8479b1..43e692a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -774,6 +774,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1815,
+/**/
     1814,
 /**/
     1813,