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
• ZeroTrie types simplification #4408: Run performance benchmarks again to see if we can consolidate the flavors of ZeroTrie down to two or one