Change: (helm-org-ql) Disable highlighting

Doesn't work properly because input contains predicates and keywords
that shouldn't be highlighted.  Might try to fix it someday to only
use args to (regexp) and (heading).

helm-org-ql.el

@@ -197,6 +197,7 @@ Is transformed into this query:
     :match #'identity
     :fuzzy-match nil
     :multimatch nil
+    :nohighlight t
     :volatile t
     :keymap helm-org-ql-map
     :action helm-org-ql-actions))