Function generate_text_columns

pub(super) fn generate_text_columns(
    retrieved_references: &RetrievedSourceReferences,
    text_columns: &mut [UnresolvedItemName],
) -> Result<BTreeMap<u32, BTreeSet<String>>, PlanError>

Generate a mapping of Oids to column names that should be ingested as text (rather than their type in the upstream database).

Additionally, modify text_columns so that they contain database-qualified references to the columns.