Capitalize T and add mssing periods

Existing Wording:

Each MessageHeader must have:

1. A code for the type of event
2. the message source application
3. A reference to the event’s focus resource(s) which will be bundled in the message.

Each MessageHeader must support:
1. A destination

Proposed Wording:

Each MessageHeader must have:

1. A code for the type of event\.
2\. The message source application\.
3\. A reference to the event’s focus resource(s) which will be bundled in the message\.

Each MessageHeader must support:
1\. A destination\.