Handle fuzzy search

[fulmicoton]

Handle matching with a given levenshtein distance of at most k.
k should be a function of the length of the query though.

It might be nice to contribute to the fst crate with the original implementation of levenshtein automaton.

[drusellers]

https://github.com/BurntSushi/fst/blob/master/fst-levenshtein/src/lib.rs has the fst code.

@fulmicoton would this be a collector?

[fulmicoton]

No, probably a query...

We want something that intersects the term dictionary with the levenshtein automaton like what you see in BurntSushi code.

Maybe we should just pre-compute the full docset of documents that match the fuzzy query, and then have the scorer iterate over those, I am unsure.

[rhanka]

Is this feature officially out of scope ?

[fulmicoton]

No. It is not out of scope. It will happen eventually.

If you want fuzzy search on one term, the FuzzyTermQuery does it.
The levenshtein automata stuff has been implemented, and is compatible with the fst crate.

[shikhar]

Dupe or at least related: #563