Track special words found in some descriptions, like "index", "supplement", and "incomplete"

If these words are tracked in the data when descriptions are being parsed, it'll allow us to override the default description regeneration patterns.

Start by locating the description-parsing entry point and the data structure holding parsed records, then trace where default description regeneration patterns are selected. Define how words such as "index", "supplement", and "incomplete" are retained in parsed data and verify that the regeneration logic can use them to override its defaults.

Written by the indexing model from the issue text.