Improve test for no import options in DocTest tests (#6094)
Improve test for no import options in DocTest tests (#6094)

It was really confusing that a min function is return a max value.
Additionally it adds a test that defines a function a colliding name in Kernel,
that is that not conflict because it is not being imported.
ggcampinho/elixir,kimshrier/elixir,beedub/elixir,beedub/elixir,pedrosnk/elixir,antipax/elixir,gfvcastro/elixir,lexmag/elixir,kelvinst/elixir,michalmuskala/elixir,joshprice/elixir,gfvcastro/elixir,elixir-lang/elixir,antipax/elixir,ggcampinho/elixir,kimshrier/elixir,pedrosnk/elixir,lexmag/elixir,kelvinst/elixir