Move nlsdownlevel.h into winapinls.cpp (#188)

[chris0x44]

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[CaseyCarter]

Looks good - this is almost [NFC], so it shouldn't require additional test coverage.

(Stephan adds: "NFC" means No Functional Changes.)

[CaseyCarter]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[StephanTLavavej]

As Casey predicted, Azure Pipelines detected that clang-format needs to be run on this file.

[StephanTLavavej]

By the way, thanks for working on this!

Note to self: after this is revised and merged on GitHub, we will need to make a Microsoft-internal change to remove nlsdownlevel.h from "setup authoring" (which installs the file as part of Visual Studio). The setup authoring files that need to be changed are for the entire MSVC toolset, which is why they can't be part of this GitHub repo.

[StephanTLavavej]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[StephanTLavavej]

I've made those Microsoft-internal changes and I'm running this through our build system.

[StephanTLavavej]

Thanks for the improvement, and congratulations on your first commit to the STL!

Now that you've made the tables constexpr, @CaseyCarter suggested a further improvement that will be possible in the future, which I've filed as #224.

[chris0x44]

Thanks :) I'll keep an eye on #224