Apply suggestions from code review

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

Author: mcabbott

src/projection.jl

@@ -223,9 +223,7 @@ function (project::ProjectTo{AbstractArray})(dx::AbstractArray{S,M}) where {S,M}
 end
 
 # Trivial case -- won't collapse Any[NoTangent(), NoTangent()]
-function (project::ProjectTo{AbstractArray})(dx::AbstractArray{<:AbstractZero})
-    return NoTangent()
-end
+(project::ProjectTo{AbstractArray})(dx::AbstractArray{<:AbstractZero}) = NoTangent()
 
 # Row vectors aren't acceptable as gradients for 1-row matrices:
 function (project::ProjectTo{AbstractArray})(dx::LinearAlgebra.AdjOrTransAbsVec)

test/projection.jl

@@ -71,8 +71,8 @@ Base.zero(x::Dual) = Dual(zero(x.value), zero(x.partial))
         @test prow(adjoint([1, 2, 3])) isa Matrix
 
         # some bugs
-        @test pvec3(fill(NoTangent(), 3)) === NoTangent() #410, was an array of such
-        @test ProjectTo([pi])([1]) isa Vector{Int} #423, was Irrational -> Bool -> NoTangent
+        @test pvec3(fill(NoTangent(), 3)) === NoTangent()  #410, was an array of such
+        @test ProjectTo([pi])([1]) isa Vector{Int}  #423, was Irrational -> Bool -> NoTangent
     end
 
     @testset "Base: arrays of arrays, etc" begin