Move away from deprecated `users` to `uzers` #285

Job	Run time
Lints, pinned toolchain	34s
Tests, unstable toolchain (beta)	17s
Tests, unstable toolchain (nightly)	30s
Tests (release), stable toolchain	26s
Tests (release), minimum supported toolchain	31s
Tests, stable toolchain	16s
	2m 34s

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