[vala] Revert "libvaladoc: Avoid superfluous references of Rule"

[Rico Tzschichholz <ricotz src gnome org>]

commit 981067135665b69bf72248bd1dd3dc108d866652
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Wed Jun 13 15:20:14 2018 +0200

    Revert "libvaladoc: Avoid superfluous references of Rule"
    
    This reverts commit 85d3dffc0e8dfaf6549a730be918aece7afff951.

 libvaladoc/parser/rule.vala | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/libvaladoc/parser/rule.vala b/libvaladoc/parser/rule.vala
index 410eef14b..88be423c7 100644
--- a/libvaladoc/parser/rule.vala
+++ b/libvaladoc/parser/rule.vala
@@ -64,19 +64,19 @@ public abstract class Valadoc.Rule : Object {
 
        public delegate void Action () throws ParserError;
 
-       public unowned Rule set_start (Action action) {
+       public Rule set_start (Action action) {
                //TODO: Ownership Transfer
                _start_action = () => { action (); };
                return this;
        }
 
-       public unowned Rule set_reduce (Action action) {
+       public Rule set_reduce (Action action) {
                //TODO: Ownership Transfer
                _reduce_action = () => { action (); };
                return this;
        }
 
-       public unowned Rule set_skip (Action action) {
+       public Rule set_skip (Action action) {
                //TODO: Ownership Transfer
                _skip_action = () => { action (); };
                return this;