Provide convenience method addTextCrumb() to PhabricatorCrumbsView

Summary: We currently have a lot of calls to `addCrumb(id(new PhabricatorCrumbView())->...)` which can be expressed much more simply with a convenience method. Nearly all crumbs are only textual.

Test Plan:
  - This was mostly automated, then I cleaned up a few unusual sites manually.
  - Bunch of grep / randomly clicking around.

Reviewers: btrahan, chad

Reviewed By: btrahan

CC: hach-que, aran

Differential Revision: https://secure.phabricator.com/D7787

src/applications/differential/controller/DifferentialDiffCreateController.php

@@ -88,9 +88,7 @@ final class DifferentialDiffCreateController extends DifferentialController {
       ->setForm($form);
 
     $crumbs = $this->buildApplicationCrumbs();
-    $crumbs->addCrumb(
-      id(new PhabricatorCrumbView())
-        ->setName(pht('Create Diff')));
+    $crumbs->addTextCrumb(pht('Create Diff'));
 
     if ($errors) {
       $errors = id(new AphrontErrorView())