Removes lazy_static in favor of OnceLock.

[Dygear]

The goal here was simply to remove lazy_static in favor of the the standard lib functions that replaced it. This is the smallest number of code changes that I could create to make that happen. I have tested this in my own project and it works as it did before.

[spenserblack]

Because SHOULD_COLORIZE is public, and the usage now requires calling get_or_init, I believe this counts as a breaking change.

Perhaps until the API from once_cell is fully stabilized as part of the standard library (rust-lang/rust#121377) once_cell::sync::Lazy from the once_cell crate can be used.