Fix "are are" in explanatory text

Summary: See rP8806fb0296c2.

Test Plan:
me fail english

with bonus!

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D10514

src/applications/config/option/PhabricatorCoreConfigOptions.php

@@ -106,7 +106,7 @@ final class PhabricatorCoreConfigOptions
             "\n\n".
             "Phabricator includes prototype applications which are in an ".
             "**early stage of development**. By default, prototype ".
-            "applications are not installed, because are are often not yet ".
+            "applications are not installed, because they are often not yet ".
             "developed enough to be generally usable. You can enable ".
             "this option to install them if you're developing Phabricator ".
             "or are interested in previewing upcoming features.".

src/applications/files/engineselector/PhabricatorFileStorageEngineSelector.php

@@ -23,7 +23,7 @@ abstract class PhabricatorFileStorageEngineSelector {
    * Phabricator when it needs to store a file permanently. It must return a
    * list of valid @{class:PhabricatorFileStorageEngine}s.
    *
-   * If you are are extending this class to provide a custom selector, you
+   * If you are extending this class to provide a custom selector, you
    * probably just want it to look like this:
    *
    *   return array(new MyCustomFileStorageEngine());