Reduce std.getopt compile time by removing std.format calls

[burner]

calling std.format, even though an awesome library, increases compile time quite a bit. This PR removes most calls to std.format.format.

[dlang-bot]

Thanks for your pull request, @burner!

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Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + phobos#10839"

[burner]

other PR's in this series

• Decrease compile time s-ludwig/taggedalgebraic#77
• Reduce compile time vibe-d/vibe.d#2830
• Decrease Compile Time vibe-d/vibe-core#435

[burner]

@thewilsonator thank you