Edit ios-builds-on-os-x.md

Fix localization mistake. Documentation uses US English spelling and in this document we were using 'organisation' not 'organization'. Organisation is primarily only used in UK English.

Author: Willow Graysen

jekyll/_cci1/ios-builds-on-os-x.md

@@ -317,7 +317,7 @@ your organization's settings page.
 
 ![](  {{ site.baseurl }}/assets/img/docs/fabric-org-settings-page.png)
 
-Click on your organisation (CircleCI in the image above), and click on
+Click on your organization (CircleCI in the image above), and click on
 the API key and Build Secret links to reveal the items.
 
 ![](  {{ site.baseurl }}/assets/img/docs/fabric-api-creds-page.png)