feat(rust!,python): Add Series.cat.uses_lexical_ordering

[stinodego]

Closes #5671, supersedes #5705, blocker for #10267

I didn't want to rebase the existing PR, so here's a fresh PR.

WARNING: This functionality is considered experimental for now.

Changes:

• On the Rust side:
  • Rename set_lexical_sorted to set_lexical_ordering.
  • Rename bit setting LEXICAL_SORT to LEXICAL_ORDERING.
  • Rename use_lexical_sort to uses_lexical_ordering and make it public outside the crate
• On the Python side:
  • Expose the uses_lexical_ordering method for categorical Series.

I am really looking for a better name for this method, but I'm struggling to come up with something good. Help is appreciated!
I initially thought is_ordered would be appropriate. That would be the reverse of this - an ordered categorical sorts by physical type rather than lexical. -> Chose a sensible name for now and marked as experimental.

[orlp]

Why not just get_ordering returning "lexical" or "physical" just like the input of set_ordering?

[stinodego]

Why not just get_ordering returning "lexical" or "physical" just like the input of set_ordering?

That makes sense with the current API, though I don't like having to check the result versus a string, when I know there are only two options. It's both inefficient and easy to mess up.

We should probably change set_ordering too, at some point. For the same reason.

I think I'll just slap an "experimental" tag on this for now and merge it as-is. We can revisit later.

[stinodego]

@ritchie46 I chose a slightly different name / renamed related functionality on the Rust side. Are you OK with this?

[ritchie46]

@ritchie46 I chose a slightly different name / renamed related functionality on the Rust side. Are you OK with this?

Yeap.