Diffusion commits: add some edge phrases about Revisions

Summary:
This change implements some messages that were only present
from this class:

DifferentialRevisionHasCommitEdgeType.php

But not in its inverse class:

DiffusionCommitHasRevisionEdgeType.php

In short:

| Before | After |
|-----------|-----------|
| {F313282} | {F313281} |

Closes T15314

Test Plan:
Visit a Diffusion commit and use the sidebar menu "Edit Related Objects" to:

- add 1 revision
- add 2 revisions
- remove 1 revision
- remove 2 revisions
- add 1 revision, remove 1 revision
- add 2 revisions, remove 2 revisions

Check that you don't see phrases like "added an edge" anymore.

Reviewers: O1 Blessed Committers, avivey

Reviewed By: O1 Blessed Committers, avivey

Subscribers: speck, tobiaswiese, Matthew, Cigaryno

Maniphest Tasks: T15314

Differential Revision: https://we.phorge.it/D25306

src/applications/diffusion/edge/DiffusionCommitHasRevisionEdgeType.php

···
       'The source commit is associated with the destination revision.');
   }
 
+  public function getTransactionAddString(
+    $actor,
+    $add_count,
+    $add_edges) {
+
+    return pht(
+      '%s added %s revision(s): %s.',
+      $actor,
+      $add_count,
+      $add_edges);
+  }
+
+  public function getTransactionRemoveString(
+    $actor,
+    $rem_count,
+    $rem_edges) {
+
+    return pht(
+      '%s removed %s revision(s): %s.',
+      $actor,
+      $rem_count,
+      $rem_edges);
+  }
+
+  public function getTransactionEditString(
+    $actor,
+    $total_count,
+    $add_count,
+    $add_edges,
+    $rem_count,
+    $rem_edges) {
+
+    return pht(
+      '%s edited revision(s), added %s: %s; removed %s: %s.',
+      $actor,
+      $add_count,
+      $add_edges,
+      $rem_count,
+      $rem_edges);
+  }
+
 }