Tag visualization accuracy

[absempere]

@camdendotlol https://tanyaclement.github.io/znh-1939/tags/detail/speaker/library_of_congress/

There's also an issue with the tag -- the visualization shows that the tag only appears at the end of the recording, but it appears earlier in the actual annotation set: https://tanyaclement.github.io/znh-1939/events/field-recordings-t86-243/

Originally posted by @absempere in #100 (comment)