refactor: extract method output_chaps_by_file
refactor: extract method output_chaps_by_file

masawada/review,orangain/review,krororo/review,murashitas/review,orangain/review,suzuki/review,kmuto/review,krororo/review,suzuki/review,masawada/review,takahashim/review,murashitas/review,kmuto/review,kuad9/review_study,krororo/review,takahashim/review,kuad9/review_study,kmuto/review