Turn a table into the long-format token table the matching verbs work on:
it applies each column's preparation steps, splits the text into tokens, and
attaches the id and any blocking columns. The other verbs
(detect_duplicates(), search_candidates()) call this for you, so you
rarely need it directly; reach for it when you want to see or post-process
the tokens yourself.
Value
A long-format token table with one row per token, carrying the id,
the source column, the token, a row_id, and any blocking columns.
See also
inspect_tokens() for a quick per-column look at the tokens.
