MNT/DOC: move and document _event_desc_given_oid
MNT/DOC: move and document _event_desc_given_oid

tacaswell/metadataStore,ericdill/databroker,ericdill/databroker,tacaswell/metadataStore,hhslepicka/metadatastore,arkilic/metadatastore,hhslepicka/metadatastore,NSLS-II/metadatastore,arkilic/metadatastore,NSLS-II/metadatastore