patch 8.0.0402: :map completion does not have <special>

Problem:    :map completion does not have <special>. (Dominique Pelle)
Solution:   Recognize <special> in completion.  Add a test.
diff --git a/src/version.c b/src/version.c
index 932132d..e109687 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    402,
+/**/
     401,
 /**/
     400,