Render hashtags as colored/icon'd project tags

Summary: In most cases we preserve what the user typed, but showing colors/icons/names is more useful than `#yolo` (and makes aliases more usable without loss of meaning).

Test Plan: {F174510}

Reviewers: chad

Reviewed By: chad

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D9831

src/applications/project/remarkup/ProjectRemarkupRule.php

@@ -7,6 +7,14 @@ final class ProjectRemarkupRule
     return '#';
   }
 
+  protected function renderObjectRef($object, $handle, $anchor, $id) {
+    if ($this->getEngine()->isTextMode()) {
+      return '#'.$id;
+    }
+
+    return $handle->renderTag();
+  }
+
   protected function getObjectIDPattern() {
     // NOTE: This explicitly does not match strings which contain only
     // digits, because digit strings like "#123" are used to reference tasks at