Documentation for `Table` class refers to non-existent contexts

[danidiaz]

-- metadata about a column to a particular Haskell type. In Rel8, we have
-- contexts for expressions (the 'Rel8.Expr' context), aggregations (the
-- 'Rel8.Aggregate' context), insert values (the 'Rel8.Insert' contex), among
-- others.

rel8/src/Rel8/Table.hs

Line 52 in 6ec0366

-- contexts for expressions (the 'Rel8.Expr' context), aggregations (the

Unless I'm mistaken, the Aggregate and Insert contexts don't exist anymore.