patch 8.1.1228: not possible to process tags with a function

Problem:    Not possible to process tags with a function.
Solution:   Add tagfunc() (Christian Brabandt, Andy Massimino, closes #4010)
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 594abfc..0ab5df6 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -6813,7 +6813,7 @@
 
     *matches = (char_u **)"";
     *num_matches = 0;
-    flags = TAG_HELP | TAG_REGEXP | TAG_NAMES | TAG_VERBOSE;
+    flags = TAG_HELP | TAG_REGEXP | TAG_NAMES | TAG_VERBOSE | TAG_NO_TAGFUNC;
     if (keep_lang)
 	flags |= TAG_KEEP_LANG;
     if (find_tags(IObuff, num_matches, matches, flags, (int)MAXCOL, NULL) == OK