FIX printing index with display.max_seq_items=None (GH10182)
Fixes #10182 

@jreback two reasons for the failures (both because I used `repeat`):
- CategoricalIndex -> `repeat` does not work, as Categorical has no repeat method -> do I add this?
- PeriodIndex -> `repeat` removes the `freq` -> this seems like a bug? (or not specifically implemented/checked for PeriodIndex)
 I think if you remove `tseries/base/DatetimeIndexOpsMix/repeat` the `PeriodIndex` case will be fixed (as `core/index.py/Index/repeat` should work; this correctly propogates the meta-data). Obviously not tested though.

I think `CategoricalIndex` might need its own repeat, though you _might_ be able to 'combine' it with `MultiIndex.repeat` as these are pretty similar. (You can create a mixin, maybe `MultiIndexMixin`) or something to hold these (and a couple more methods IIRC).
 For the CategoricalIndex, why not adding `Categorical.repeat`? This seems rather straightforward at first sight, as repeating the codes should do? And then no logic on the Index itself has to be changed.
 @jorisvandenbossche that's what I said, add for `CategoricalIndex.repeat` (you can combine with `MultiIndex.repeat` if you want to (side issue)
 I mean `Categorical.repeat`, not `CategoricalIndex.repeat`
 @jorisvandenbossche oh, yes, for sure do that!
 @jreback can you have a look?
 this looked reasonable
 @jreback yes, coming back to this. I think your main comment here is that the tests can be expanded by looping over the `indices`. However, as I am rather busy at work this week, is it OK to leave that for another PR? Besides the whatsnew notice I think this is good to go.
 @jorisvandenbossche sure. Always like expanded tests, but otherwise ok. merge when ready.
 ok, will do this evening
