patch 8.0.0190: finding duplicate tags uses a slow linear search

Problem:    Detecting duplicate tags uses a slow linear search.
Solution:   Use a much faster hash table solution. (James McCoy, closes #1046)
            But don't add hi_keylen, it makes hash tables 50% bigger.
diff --git a/src/version.c b/src/version.c
index 368a984..2094db7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    190,
+/**/
     189,
 /**/
     188,