patch 8.2.0878: no reduce() function

Problem:    No reduce() function.
Solution:   Add a reduce() function. (closes #5481)
diff --git a/src/version.c b/src/version.c
index af3aadf..4a27140 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    878,
+/**/
     877,
 /**/
     876,