chore(data/set/intervals/unordered_interval): Rename to `uIcc`/`uIoc` (#18104)
Rename
* `set.interval` → `set.uIcc`
* `set.interval_oc` → `set.uIoc`
* `finset.interval`→ `finset.uIcc`
Closes #17982
Zulip: https://leanprover.zulipchat.com/#narrow/stream/116395-maths/topic/Set.20intervals.20names