This PR upgrades Kotlin to 1.9.20, and Ktlint to 1.0.1.

I had to abandon the pretty-format-kotlin pre-commit hook since it was
ignoring our `.editorconfig`, which made it impossible to suppress some
of the newer lints that would be difficult and undesirable to fix. Now
all Ktlint runs go through gradle, so there isn't any way for
inconsistencies to creep in.

I recommend reviewing this PR commit by commit as the commit that runs
Ktlint against the entire repo has a very large diff. When reviewing the
Ktlint formatting changes, be sure to hide whitespace changes to reduce
how much needs to be examined.

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