Correct spelling of "therefore"

Summary: Fixes T11565.

Test Plan: `git grep -i therefor | grep -vi therefore`

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11565

Differential Revision: https://secure.phabricator.com/D16476

src/applications/owners/storage/PhabricatorOwnersPath.php

@@ -88,7 +88,7 @@ final class PhabricatorOwnersPath extends PhabricatorOwnersDAO {
     $self_count = count($self_fragments);
     $path_count = count($path_fragments);
     if ($self_count > $path_count) {
-      // If this path is longer (and therefor more specific) than the target
+      // If this path is longer (and therefore more specific) than the target
       // path, we don't match it at all.
       return 0;
     }

src/docs/user/userguide/harbormaster.diviner

@@ -88,7 +88,7 @@ with {nav Add Build Step}.
 
 Currently, the only useful type of build step is "Make HTTP Request", which you
 can use to make a call to an external build system like Jenkins. Today, most
-plans should therefor look something like this:
+plans should therefore look something like this:
 
   - Use a "Make HTTP Request" step to tell Jenkins or some other similar
     external build system about the code.