Stop pirating show for NamedTuples

[sethaxen]

This line pirates show for NamedTuple.

MLJBase.jl/src/show.jl

Line 84 in 5084d32

Base.show(stream::IO, ::MIME"text/plain", t::NamedTuple) = fancy_nt(stream, t)

It differs from the existing show method in Base by inserting a newline:
https://github.com/JuliaLang/julia/blob/9375a2d9d758c8ad4fc0fbae1e36702e6aed0ada/base/namedtuple.jl#L198-L229

I ran into this when doctests for a function that returns a NamedTuple started to fail when MLJBase came into scope.

Quick demo:

julia> nt = (; x=3, y=4)
(x = 3, y = 4)

julia> using MLJBase

julia> nt
(x = 3,
 y = 4,)