Report if a given style is a common style in the applied style summary

Consumers of the applied style summary information benefit from knowing
which common styles are applied to the given selection (e.g., so the
appropriate common paragraph & text styles can be selected in the UI).
Remove non-existent parameter from API dox
Merge pull request #341 from peitschie/common-styles

Report if a given style is a common style in the applied style summary