Fix exception in Transaction Log after renaming Pholio Mock image: Call to undefined method PholioImageSequenceTransaction::renderHandleLink()

Summary:
Replace call to undefined `renderHandleLink()` with `renderHandle()`.

Additionally, pass `head_key($new)` instead of `key($new)`. This might not be needed strictly speaking for this very issue but should not harm either as several images in a mock can be renamed at once.

```
EXCEPTION: (Error) Call to undefined method PholioImageSequenceTransaction::renderHandleLink() at [<phorge>/src/applications/pholio/xaction/PholioImageSequenceTransaction.php:32]
```

Closes T15680

Test Plan:
* Rename the title of an image in a Pholio mock.
* Go to `/feed/transactions/query/all/` which now renders instead of showing an error, and shows two entries:
* `user renamed an image (newname.jpg) from oldname.jpg to newname.jpg.` and `user updated an image's (newname.jpg) sequence.`
(However, separate T15679 will still show up in the error log after this change.)

Reviewers: O1 Blessed Committers, speck

Reviewed By: O1 Blessed Committers, speck

Subscribers: speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T15680

Differential Revision: https://we.phorge.it/D25482

src/applications/pholio/xaction/PholioImageSequenceTransaction.php

@@ -29,7 +29,7 @@ final class PholioImageSequenceTransaction
     return pht(
       '%s updated an image\'s (%s) sequence.',
       $this->renderAuthor(),
-      $this->renderHandleLink(key($new)));
+      $this->renderHandle(head_key($new)));
   }
 
   public function getTitleForFeed() {