Add comma and fix typo
As mentioned, a PEP service MUST send the last published item to all new subscribers and to all newly-available resources for each subscriber, including the account owner itself. (That is, the default value of the "pubsub#send_last_published_item" node configuration field must be "on_sub_and_presence"; this behavior essentially mimics the functionality of presence as defined in XMPP IM.) When processing a new subscription, the service MAY send not only the last published item but instead all items that are currently associated with the node (i.e., up to the maximum number of items at the node, which might be one if the node is a "singleton node" as described in XEP-0060). If the service has knowledge about the datetime that a subscriber's newly-available resource last received updated information from the node (e.g., as described in &xep0256;) then it MAY also send more items that only the last published item to the newly-available resource.
+As mentioned, a PEP service MUST send the last published item to all new subscribers and to all newly-available resources for each subscriber, including the account owner itself. (That is, the default value of the "pubsub#send_last_published_item" node configuration field must be "on_sub_and_presence"; this behavior essentially mimics the functionality of presence as defined in XMPP IM.) When processing a new subscription, the service MAY send not only the last published item but instead all items that are currently associated with the node (i.e., up to the maximum number of items at the node, which might be one if the node is a "singleton node" as described in XEP-0060). If the service has knowledge about the datetime that a subscriber's newly-available resource last received updated information from the node (e.g., as described in &xep0256;), then it MAY also send more items than only the last published item to the newly-available resource.
Note: The "on_sub_and_presence" setting relates to the subscriber's presence, not the publisher's presence.