Coverage report highlights spans that don't match up to syntactic units in code

[taymonbeal]

See, e.g., frame/main.ts.html in attached output.
coverage.zip

[taymonbeal]

Update: This turns out to be because I didn't have source maps enabled in my tsconfig. I still think the tooling should have warned me about this, but that's on karma-typescript; there's nothing karma-coverage can really do about it.