Wrong scalar returned in abs, conj and sqrt in tblis_scalar

[Thoemi09]

Dear TBLIS developers,

I think there might be a bug in the abs, conj and sqrt methods of tblis_scalar, see e.g. https://github.com/MatthewsResearchGroup/tblis/blob/master/tblis/frame/base/basic_types.h#L854-L859.

As far as I understand, the methods should return ret and not other. This can lead to unexpected results when doing reductions with complex types (maybe it also affects other operations).