patch 8.0.0860: side effects when channel appends to a buffer

Problem:    There may be side effects when a channel appends to a buffer that
            is not the current buffer.
Solution:   Properly switch to another buffer before appending. (Yasuhiro
            Matsumoto, closes #1926, closes #1937)
diff --git a/src/version.c b/src/version.c
index a5e02a1..f716a4c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    860,
+/**/
     859,
 /**/
     858,