LU and QR are not <: Factorization{T}

```julia
julia> using LinearAlgebra

help?> Factorization
search: Factorization

  LinearAlgebra.Factorization

  Abstract type for matrix factorizations
  (https://en.wikipedia.org/wiki/Matrix_decomposition) a.k.a. matrix
  decompositions. See online documentation for a list of available matrix
  factorizations.
```

It should probably be subtyping that.