Switch to using singleton types to specify backend algorithm

[codecov-commenter]

Codecov Report

Patch coverage: 83.33% and project coverage change: +0.06 :tada:

Comparison is base (a52f76d) 90.30% compared to head (b2e859f) 90.37%.

:mega: This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #72 +/- ## ========================================== + Coverage 90.30% 90.37% +0.06% ========================================== Files 12 12 Lines 557 561 +4 ========================================== + Hits 503 507 +4 Misses 54 54 ``` | [Impacted Files](https://codecov.io/gh/gaurav-arya/StochasticAD.jl/pull/72?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya) | Coverage Δ | | |---|---|---| | [src/backends/smoothed.jl](https://codecov.io/gh/gaurav-arya/StochasticAD.jl/pull/72?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya#diff-c3JjL2JhY2tlbmRzL3Ntb290aGVkLmps) | `81.81% <ø> (ø)` | | | [src/finite\_infinitesimals.jl](https://codecov.io/gh/gaurav-arya/StochasticAD.jl/pull/72?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya#diff-c3JjL2Zpbml0ZV9pbmZpbml0ZXNpbWFscy5qbA==) | `100.00% <ø> (ø)` | | | [src/stochastic\_triple.jl](https://codecov.io/gh/gaurav-arya/StochasticAD.jl/pull/72?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya#diff-c3JjL3N0b2NoYXN0aWNfdHJpcGxlLmps) | `76.47% <60.00%> (ø)` | | | [src/backends/dict.jl](https://codecov.io/gh/gaurav-arya/StochasticAD.jl/pull/72?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya#diff-c3JjL2JhY2tlbmRzL2RpY3Quamw=) | `90.47% <100.00%> (+0.15%)` | :arrow_up: | | [src/backends/pruned.jl](https://codecov.io/gh/gaurav-arya/StochasticAD.jl/pull/72?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya#diff-c3JjL2JhY2tlbmRzL3BydW5lZC5qbA==) | `91.30% <100.00%> (+0.12%)` | :arrow_up: | | [src/backends/pruned\_aggressive.jl](https://codecov.io/gh/gaurav-arya/StochasticAD.jl/pull/72?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya#diff-c3JjL2JhY2tlbmRzL3BydW5lZF9hZ2dyZXNzaXZlLmps) | `91.07% <100.00%> (+0.33%)` | :arrow_up: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Gaurav+Arya)

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Do you have feedback about the report comment? Let us know in this issue.

[mschauer]

That's good