Fix typespec for DynamicSupervisor.on_start_child (#7590)
Fix typespec for DynamicSupervisor.on_start_child (#7590)


kelvinst/elixir,lexmag/elixir,ggcampinho/elixir,kimshrier/elixir,elixir-lang/elixir,pedrosnk/elixir,pedrosnk/elixir,michalmuskala/elixir,ggcampinho/elixir,kimshrier/elixir,kelvinst/elixir,joshprice/elixir,lexmag/elixir