@non_differentiable with Varargs for string concatenation

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i.e. in Base/nondiff.jl

@non_differentiable *(::Union{Regex, AbstractChar, AbstractString})
@non_differentiable *(
    ::Union{Regex, AbstractChar, AbstractString},
    ::Union{Regex, AbstractChar, AbstractString},
)
@non_differentiable *(
    ::Union{Regex, AbstractChar, AbstractString},
    ::Union{Regex, AbstractChar, AbstractString},
    ::Union{Regex, AbstractChar, AbstractString},
)

can now (after JuliaDiff/ChainRulesCore.jl#254 and #339 missed this, my bad) be rewritten as

@non_differentiable *(::Union{Regex, AbstractChar, AbstractString}...)

[mzgubic]

Similarly for Core.print and Core.println in Core/core.jl

[mzgubic]

was looking at an old branch...