fixing width and improper colon use in distgit directive docs
    
    Summary: the docs weren't building due to improper colon use and the line length was too long. fixed both issues so that docs are OK and build for release
    
    Test Plan: build docs, it works
    
    Reviewers: kparal
    
    Subscribers: jskladan, mkrizek, tflink
    
    Differential Revision: https://phab.qadevel.cloud.fedoraproject.org/D445