feat(topology/support): add lemmas, fix a name (#15484)
* generalize `support_smul_subset_left` to `smul_with_zero`;
* add `tsupport_smul_subset_left`;
* rename `not_mem_closure_mul_support_iff_eventually_eq` to
`not_mem_mul_tsupport_iff_eventually_eq`;
* add `continuous_of_mul_tsupport`.
