feat(linter): implement unicorn/custom-error-definition rule

[baevm]

this PR adds unicorn/custom-error-definition rule, passes all original tests

issue #684

[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 52 skipped benchmarks¹

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_{Comparing baevm:custom-error-def (2798270) with main (6cd513f)²}

Footnotes

1. 52 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on main (6528f37) during the generation of this report, so 6cd513f was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[camc314]

Thank you!