Formatting with SimpleTraits.jl

[theogf]

Moving issue JunoLab/Juno.jl#529 here.
Using SimpleTraits.jl, the formatter fails when seeing this line:
@traitfn function predict_ar(m::TGP, p::Int = 3, n::Int = 1; y_past = get_y(m)) where {T,TGP<:AbstractGP{T};IsMultiOutput{TGP}}
both when applying on the line alone or on the whole function

[domluna]

so ; in the where condition is causing this error. It should be an easy fix, never seen ; used like this before

[theogf]

Yes exactly it decides if a type satisfy some condition, it kind of replaces multiple inheritance