Update test/downstream/solve_error_handling.jl

Author: ChrisRackauckas

test/downstream/solve_error_handling.jl

@@ -37,7 +37,7 @@ prob = ODEProblem{false}(f, (1.0, 1.0f0), tspan)
 prob = ODEProblem{false}(f, u0, (0.0 + im, 1.0))
 @test_throws DiffEqBase.ComplexTspanError solve(prob, Tsit5())
 
-for u0 = ([0.0, 0.0], nothing
+for u0 in ([0.0, 0.0], nothing)
     fmm = ODEFunction(f, mass_matrix = zeros(3, 3))
     prob = ODEProblem(fmm, u0, (0.0, 1.0))
     @test_throws DiffEqBase.IncompatibleMassMatrixError solve(prob, Tsit5())