Show for `Tensorizer`

[jishnub]

After this,

julia> ApproxFunBase.tensorizer(Chebyshev()^2)
ApproxFunBase.Tensorizer((Ones(ℵ₀), Ones(ℵ₀)))

vs master

julia> ApproxFunBase.tensorizer(Chebyshev()^2)
ApproxFunBase.Tensorizer{Tuple{FillArrays.Ones{Int64, 1, Tuple{InfiniteArrays.OneToInf{Int64}}}, FillArrays.Ones{Int64, 1, Tuple{InfiniteArrays.OneToInf{Int64}}}}}((Ones(ℵ₀), Ones(ℵ₀)))

Also, restricts Tensorizer to tuples of AbstractVector{Int}.

[codecov[bot]]

Codecov Report

Patch coverage: 53.84% and project coverage change: +0.06% :tada:

Comparison is base (414e1c5) 27.56% compared to head (a411db2) 27.62%. Report is 3 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #550 +/- ## ========================================== + Coverage 27.56% 27.62% +0.06% ========================================== Files 80 80 Lines 8380 8387 +7 ========================================== + Hits 2310 2317 +7 Misses 6070 6070 ``` | [Files Changed](https://app.codecov.io/gh/JuliaApproximation/ApproxFunBase.jl/pull/550?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaApproximation) | Coverage Δ | | |---|---|---| | [src/Multivariate/ProductFun.jl](https://app.codecov.io/gh/JuliaApproximation/ApproxFunBase.jl/pull/550?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaApproximation#diff-c3JjL011bHRpdmFyaWF0ZS9Qcm9kdWN0RnVuLmps) | `0.00% <0.00%> (ø)` | | | [src/Multivariate/TensorSpace.jl](https://app.codecov.io/gh/JuliaApproximation/ApproxFunBase.jl/pull/550?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaApproximation#diff-c3JjL011bHRpdmFyaWF0ZS9UZW5zb3JTcGFjZS5qbA==) | `43.09% <100.00%> (+0.15%)` | :arrow_up: | | [src/Operators/Operator.jl](https://app.codecov.io/gh/JuliaApproximation/ApproxFunBase.jl/pull/550?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaApproximation#diff-c3JjL09wZXJhdG9ycy9PcGVyYXRvci5qbA==) | `51.98% <100.00%> (+0.10%)` | :arrow_up: | | [src/Operators/banded/Conversion.jl](https://app.codecov.io/gh/JuliaApproximation/ApproxFunBase.jl/pull/550?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaApproximation#diff-c3JjL09wZXJhdG9ycy9iYW5kZWQvQ29udmVyc2lvbi5qbA==) | `28.12% <100.00%> (+1.14%)` | :arrow_up: | | [src/Operators/general/algebra.jl](https://app.codecov.io/gh/JuliaApproximation/ApproxFunBase.jl/pull/550?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaApproximation#diff-c3JjL09wZXJhdG9ycy9nZW5lcmFsL2FsZ2VicmEuamw=) | `66.22% <100.00%> (+0.79%)` | :arrow_up: |

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.