Ref T6500, Duplicated tasks should be marked more visibly as duplicates

Summary: When merging tasks, the corresponding transaction on the merged task should be black, and the transaction on the ultimate task should be green.

Test Plan: Create two tasks, merge one into the other, merged task transaction is black, the surviving task should show a green transaction.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: chad, Korvin, epriestley

Maniphest Tasks: T6500

Differential Revision: https://secure.phabricator.com/D10827

Author: lkassianik

src/applications/maniphest/storage/ManiphestTransaction.php

@@ -213,6 +213,11 @@ public function getColor() {
           return 'yellow';
         }
 
+      case self::TYPE_MERGED_FROM:
+        return 'orange';
+
+      case self::TYPE_MERGED_INTO:
+        return 'black';
     }
 
     return parent::getColor();
@@ -591,7 +596,7 @@ public function getTitle() {
 
       case self::TYPE_MERGED_INTO:
         return pht(
-          '%s merged this task into %s.',
+          '%s closed this task as a duplicate of %s.',
           $this->renderHandleLink($author_phid),
           $this->renderHandleLink($new));
         break;