`string(x::Interval)` is not working correctly

[dpsanders]

julia> using IntervalArithmetic

julia> x = interval(1, 2)
[1.0, 2.0]_com

julia> string(x)
"Interval{Float64}(1.0, 2.0, com)"

string(x) should return the string version of what is displayed.

This points to a possible issue in the implementation of Base.show(io::IO, x::Interval)

[OlivierHnt]

Good catch. Should be fixed with the PR #644.