DOC: Add better examples to find_headers docstring.
DOC: Add better examples to find_headers docstring.

danielballan/datamuxer,NSLS-II/datamuxer,danielballan/dataportal,ericdill/databroker,tacaswell/dataportal,ericdill/databroker,tacaswell/dataportal,danielballan/dataportal,danielballan/datamuxer,NSLS-II/dataportal,ericdill/datamuxer,NSLS-II/dataportal,ericdill/datamuxer