Standardization across multiple formulas in the entailment

[melvic-ybanez]

Right now, standardization is only applied to each formula separately. This can result to issues such as the one (partly) resolved by introducing Skolem suffixes. This is explained in detail in this release: https://github.com/melvic-ybanez/lohika/releases/tag/v0.2.1.

While the idea of Skolem suffixes can fix the issue with generated functions and constants, nothing is stopping the user from creating their own, with names that also have those suffixes. So, in rare(?) circumstances, a name clash can still occur.

The better way to fix this issue for good is to standardized everything in the entailment.

For now, we can only discourage users from naming constants and functions with Skolem suffixes, at least until this ticket is closed.

[melvic-ybanez]

Closed by 002248e, 27d74c0, and 9f08f34