Introduce "local names" for commits

Summary: Ref T4245. Full commit display names (like `rPaaaa`) are going to be obnoxious soon in some cases (e.g., `rPaaaa` becomes `R123:aaaa`, which is much uglier) so reduce how often we show the repository in cases where it isn't really necessary to include it.

Test Plan:
  - Saw no more `rX` on repository list view for Git/Mercurial (still present for Subversion).
  - Saw no more `rX` on various repository detail views, except when referencing other commits (e.g., mentions).
  - Grepped for removed `getShortName()`.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4245

Differential Revision: https://secure.phabricator.com/D14990

src/applications/repository/query/PhabricatorRepositorySearchEngine.php

@@ -160,10 +160,16 @@ final class PhabricatorRepositorySearchEngine
 
       $commit = $repository->getMostRecentCommit();
       if ($commit) {
-        $commit_link = DiffusionView::linkCommit(
-          $repository,
-          $commit->getCommitIdentifier(),
-          $commit->getSummary());
+        $commit_link = phutil_tag(
+          'a',
+          array(
+            'href' => $commit->getURI(),
+          ),
+          pht(
+            '%s: %s',
+            $commit->getLocalName(),
+            $commit->getSummary()));
+
         $item->setSubhead($commit_link);
         $item->setEpoch($commit->getEpoch());
       }