Support "control" and "return/enter" in the remarkup rule for keystrokes

Summary: These characters are missing support in `{key ...}` but are reasonable to include.

Test Plan: {F8302969}

Differential Revision: https://secure.phabricator.com/D21508

src/infrastructure/markup/rule/PhabricatorKeyboardRemarkupRule.php

@@ -61,6 +61,22 @@ final class PhabricatorKeyboardRemarkupRule extends PhutilRemarkupRule {
           'escape',
         ),
       ),
+      array(
+        'name' => pht('Enter'),
+        'symbol' => "\xE2\x8F\x8E",
+        'aliases' => array(
+          'enter',
+          'return',
+        ),
+      ),
+      array(
+        'name' => pht('Control'),
+        'symbol' => "\xE2\x8C\x83",
+        'aliases' => array(
+          'ctrl',
+          'control',
+        ),
+      ),
       array(
         'name' => pht('Up'),
         'symbol' => "\xE2\x86\x91",