v0.89.1: itemNoun grammatical number on toolkit count lines

Patch release: grammatical number on the admin-toolkit's count and range lines.

Added

• itemNoun(count, label) and ItemLabel ({ one: string; many: string }) join the
  admin-toolkit subpath's formatters, and Pagination's and ListToolbar's itemLabel prop
  widens to string | ItemLabel. An { one, many } pair picks the grammatical number on every
  count and range line ("1 class", "6 classes"), graduating the fix aksailingclub-org's own
  toolkit proved for the "1 households" defect. A plain-string itemLabel renders exactly as
  before.

No consumer action is required.