Update test/utils.jl

Co-authored-by: Lyndon White <oxinabox@ucc.asn.au>

Author: mcabbott

test/utils.jl

@@ -26,6 +26,7 @@ VERSION > v"1.6-" && @testset "diagonal hessian" begin
     # Gradient of ^ may contain log(complex(...)), which interacts badly with Dual below Julia 1.6:
     # julia> log(ForwardDiff.Dual(1,0) + 0im) # ERROR: StackOverflowError:
     # https://github.com/JuliaDiff/ChainRules.jl/issues/525
+    # Fixed in 1.6 by: https://github.com/JuliaLang/julia/pull/36030
     xs, y = randn(2,3), rand()
     f34(xs, y) = xs[1] * (sum(xs .^ (1:3)') + y^4)  # non-diagonal Hessian, two arguments