Fix method amib. in convert(BackendRef)

Author: nHackel

src/definitions.jl

@@ -68,7 +68,7 @@ end
 Base.setindex!(ref::BackendReference, val::Union{Missing, AbstractFFTBackend}) = ref.ref[] = val
 Base.setindex!(ref::BackendReference, val::Module) = setindex!(ref, val.backend())
 Base.getindex(ref::BackendReference) = getindex(ref.ref)
-Base.convert(BackendReference, val::AbstractFFTBackend) = BackendReference(val)
+Base.convert(::Type{BackendReference}, val::AbstractFFTBackend) = BackendReference(val)
 const fft_backend = ScopedValue(BackendReference(missing))
 
 """