fixed <did> elements

<did> Elements and unittitles marked up incorrectly

git-svn-id: https://subversion.lib.virginia.edu/repos/ead/branches/pub-schema/uva-sc@10782 6d43c525-cd11-0410-ac62-a67304e79d8a
Merge branch 'pub-schema' of https://github.com/uvalib-dcs/VH_uva-sc into pub-schema