Clean up ExUnit.Assertions docs
Clean up ExUnit.Assertions docs

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Conflicts:
	lib/ex_unit/lib/ex_unit/assertions.ex

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