patch 8.0.0229: local 'formatprg' option value leaks

Problem:    When freeing a buffer the local value of the 'formatprg' option is
            not cleared.
Solution:   Add missing change.
diff --git a/src/version.c b/src/version.c
index 6d3b848..829b3b9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    229,
+/**/
     228,
 /**/
     227,