feat(init/data/bool): simplify defn of band/bor (#466)
feat(init/data/bool): simplify defn of band/bor (#466)

Everything (including mathlib) compiles cleanly with no other changes, apparently.

Per request at https://leanprover.zulipchat.com/#narrow/stream/113489-new-members/topic/band.2C.20bor

Co-authored-by: Scott Morrison <63f04b4d96235eb042cc46d94f14d241d2a26722@gmail.com>
Co-authored-by: Bryan Gin-ge Chen <6e05157ce10643a7cfc5a3d4e29e4fa5cffe1fc6@gmail.com>

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