feat(data/rat/defs): inv_coe_{int,nat}_{num,denom} (#15863)
feat(data/rat/defs): inv_coe_{int,nat}_{num,denom} (#15863)

Rename existing lemmas to
`inv_coe_{int,nat}_{num,denom}_of_pos`
since they took positivity assumptions
Also provide `rat.inv_neg`.





Co-authored-by: Yakov Pechersky <9925c0c20eafe10b1eaac37c5fe124dc0b28ca8c@users.noreply.github.com>

leanprover-community/mathlib,leanprover-community/mathlib