Add header icons to PHUIPropertyListView

Summary: Adds summary (description) and test plan icons to make these area's more unique and differentiated over general sections.

Test Plan: Test a diff, a commit, a task

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7493

src/applications/diffusion/controller/DiffusionCommitController.php

@@ -131,7 +131,9 @@ final class DiffusionCommitController extends DiffusionController {
       $property_list->setActionList($headsup_actions);
 
       $detail_list = new PHUIPropertyListView();
-      $detail_list->addSectionHeader(pht('Description'));
+      $detail_list->addSectionHeader(
+        pht('Description'),
+        PHUIPropertyListView::ICON_SUMMARY);
       $detail_list->addTextContent(
         phutil_tag(
           'div',