ZeroTrie follow-ups

[sffc]

The big ZeroTrie PR was merged as #2722

• [ ] Clarify what "bracket a window of strings" means in builder/mod.rs
• [ ] Should the get function be bounded on AsRef or Borrow? If Borrow, then get_str needs to be added
• [ ] Add DataBake impls and test whether they negatively impact compile times
• [ ] #4408: Run performance benchmarks again to see if we can consolidate the flavors of ZeroTrie down to two or one