feat(order/filter/archimedean): in an archimedean linear ordered ring, `at_top` and `at_bot` are countably generated (#7751)
feat(order/filter/archimedean): in an archimedean linear ordered ring, `at_top` and `at_bot` are countably generated (#7751)






leanprover-community/mathlib,leanprover-community/mathlib