Be precise in documentation about after values in Kernel.SpecialForms.receive/1 (#7856)
Be precise in documentation about after values in Kernel.SpecialForms.receive/1 (#7856)

* 4_294_967_295 is still a valid number
* it is not correct to say that :infinity is the same as not using a timeout value,
  as this is needed if used the after clause. To what's equivalent is as to not to
  use the after clause itself.
* use the formal name "hexadecimal notation" in favor of "hex notation"

[ci skip]
kelvinst/elixir,michalmuskala/elixir,kelvinst/elixir,pedrosnk/elixir,pedrosnk/elixir,joshprice/elixir,lexmag/elixir,lexmag/elixir,kimshrier/elixir,elixir-lang/elixir,kimshrier/elixir,ggcampinho/elixir,ggcampinho/elixir