chore(order/filter/basic): golf a few proofs (#14078)
* golf the proof of `mem_generate_iff` by using `sInter_mem`;
* use `set.inj_on` in the statement of `filter.eq_of_map_eq_map_inj'`;
* golf the proofs of `filter.map_inj` and `filter.comap_ne_bot_iff`.
