feat: upgrade tantivy to 0.22

[cjrh]

NOTE: This is intentionally still a rough WIP (Sunday night hack time!). I want to get feedback on the macro changes first before putting in more work.

Two changes in tantivy 0.21 -> 0.22 that made the upgrade a little tricky:

• tantivy::schema::document::Document is now a trait
• tantivy::schema::document::Value is now a trait

We use these a fair bit, especially Value. However, I did some research and experimentation and it seems to me that we can use TantivyDocument (implements the now-trait Document) and OwnedValue (implements the now-trait Value).

The tests are passing. Is this the correct way to go?

If this is the right way to go, I'll proceed to clean up the messy bits in the next couple days and get it merged.

[adamreichold]

The tests are passing. Is this the correct way to go?

Using TantivyDocument and OnwedValue is definitely the way to go if everything should continue to work as it does.

Making use of the new flexibility offered by the Document and Value is usually a follow-up in Rust code bases and I do not think it makes in the Python wrapper because need to handle generic documents without additional knowledge of their structure. It could be that we someday have a special document wrapper that directly uses Python compatible types, i.e. implement Document for our local Document struct.