bpo-38291: Remove mention of typing.io and typing.re again (GH-26113)

They were originally removed in GH-10173 per bpo-35089, but then
readded in GH-21574. Cf. bpo-38291 for decision to remove.
(cherry picked from commit 8a76683c)

Co-authored-by: Sebastian Rittau <srittau@rittau.biz>