Add MS doc link of changing attachment size limit in MS Outlook.

en_US/howto/1-change.mail.attachment.size.md

@@ -148,3 +148,5 @@ Notes:
 
 * Exit Registry Editor
 * Start Outlook.
+
+Reference: <https://support.microsoft.com/en-us/kb/2222370>

html/change.mail.attachment.size-zh_CN.html

@@ -146,7 +146,8 @@ HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\Outlook\Preferences
 <ul>
 <li>退出注册表编辑器。</li>
 <li>启动 Outlook。</li>
-</ul><div class="footer">
+</ul>
+<p>参考文档： <a href="https://support.microsoft.com/en-us/kb/2222370">https://support.microsoft.com/en-us/kb/2222370</a></p><div class="footer">
     <p style="text-align: center; color: grey;">All documents are available in <a href="https://bitbucket.org/zhb/iredmail-docs/src">BitBucket repository</a>, and published under <a href="http://creativecommons.org/licenses/by-nd/3.0/us/" target="_blank">Creative Commons</a> license. You can <a href="https://bitbucket.org/zhb/iredmail-docs/get/tip.tar.bz2">download the latest version</a> for offline reading. If you found something wrong, please do <a href="http://www.iredmail.org/contact.html">contact us</a> to fix it.</p>
 </div>
 <script type="text/javascript">

html/change.mail.attachment.size.html

@@ -159,7 +159,8 @@ HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\Outlook\Preferences
 <ul>
 <li>Exit Registry Editor</li>
 <li>Start Outlook.</li>
-</ul><div class="footer">
+</ul>
+<p>Reference: <a href="https://support.microsoft.com/en-us/kb/2222370">https://support.microsoft.com/en-us/kb/2222370</a></p><div class="footer">
     <p style="text-align: center; color: grey;">All documents are available in <a href="https://bitbucket.org/zhb/iredmail-docs/src">BitBucket repository</a>, and published under <a href="http://creativecommons.org/licenses/by-nd/3.0/us/" target="_blank">Creative Commons</a> license. You can <a href="https://bitbucket.org/zhb/iredmail-docs/get/tip.tar.bz2">download the latest version</a> for offline reading. If you found something wrong, please do <a href="http://www.iredmail.org/contact.html">contact us</a> to fix it.</p>
 </div>
 <script type="text/javascript">

zh_CN/howto/1-change.mail.attachment.size.md

@@ -135,3 +135,5 @@ HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\Outlook\Preferences
 
 * 退出注册表编辑器。
 * 启动 Outlook。
+
+参考文档： <https://support.microsoft.com/en-us/kb/2222370>