Update email docs.

en/core-utility-libraries/email.rst

@@ -263,6 +263,8 @@ the Blog plugin.  The template file needs to be created in the following path:
 Sending attachments
 -------------------
 
+.. php:method:: attachments($attachments = null)
+
 You can attach files to email messages as well.  There are a few
 different formats depending on what kind of files you have, and how
 you want the filenames to appear in the recipient's mail client:
@@ -290,8 +292,15 @@ you want the filenames to appear in the recipient's mail client:
    Content ID (when set the content ID the attachment is transformed to inline).
    The mimetype and contentId are optional in this form.
 
-  4.1. When you are using the ``contentId``, you can use the file in the html
-  body like ``<img src="cid:my-content-id">``.
+   4.1. When you are using the ``contentId``, you can use the file in the html
+   body like ``<img src="cid:my-content-id">``.
+
+   4.2. You can use the ``contentDisposition`` option to disable the
+   ``Content-Disposition`` header for an attachment.  This is useful when
+   sending ical invites to clients using outlook.
+
+.. versionchanged:: 2.3
+    The ``contentDisposition`` option was added in 2.3
 
 Using transports
 ----------------