Move Kernel extensions into a separate file

[dduugg]

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Moves Kernel extensions to extend/kernel.rb. This makes more logical sense to me, but was motivated by making space in utils.rb for future top-level Utils method (as suggested in #14778 ). Both files remain untyped because they each rely on splats (which I'd prefer to leave out-of-scope for this PR).

I used git cp so this should preserve history. I also moved utils_spec.rb to extend/kernel_spec.rb, because all of the tests in the file appear to be Kernel extension tests.

[BrewTestBot]

Review period will end on 2023-02-27 at 18:54:36 UTC.

[apainintheneck]

Stupid question: what is git cp?

[dduugg]

Stupid question: what is git cp?

Oops, looks like that's something i have via an extension: https://github.com/tj/git-extras/blob/master/Commands.md#git-cp

But I think I misunderstood the feature, it doesn't actually appear to carry over any history to the new file 😊

[MikeMcQuaid]

Thanks, makes sense to me!

I do think, though, that many of these things could be pulled out of Kernel and into somewhere more specific. Arguably almost all of this should either be in the Homebrew module, imported into Formula and/or a Utils method or Utils::$NEWMODULE.

[BrewTestBot]

Review period ended.