sourceDescription MUST reference not emphasized

If workflows from other documents are being referenced, they MUST be included as a

MUST should be emphasized and there's a typo there.

Arazzo-Specification/versions/1.0.0.md

Line 74 in df64e14

    
           An Arazzo Description MAY be made up of a single document or be divided into multiple, connected parts at the discretion of the author. If workflows from other documents are being referenced, they must by included as a [Source Description Object](#source-description-object). In a multi-document description, the document containing the [Arazzo Specification Object](#arazzo-specification-object) is known as the **entry Arazzo document**.