This is a system-wide change. The index used to have a lexicon, mapping words to wordIds using a large in-memory hash table. This made index-construction easier, but it
also added a fairly significant RAM penalty to both the index service and the loader.
The new design moves to 64 bit word identifiers calculated using the murmur hash of the keyword, and an index construction based on merging smaller indices.
It also became necessary half-way through to upgrade guice as its error reporting wasn't *quite* compatible with JDK20.
This provides a much cleaner separation of concerns, and makes it possible to get rid of a lot of the gunkier parts of the index service. It will also permit lowering the Xmx on the index service a fair bit, so we can get CompressedOOps again :D
* Increase accuracy of the position bits.
* Increase their width to 56.
* Use a rolling position scheme for bits 16-56 to increase the average accuracy.
* Result ranking overhaul
* Optimized queries
* BM25 in the index service's ranking
* Make gui less jank
* Javadocs for ranking parameters.
* A deduplication filter step ran too early, and removed many good results on the basis that they partially, but did not fully fit another set of search terms.
* Altered the query creation process to prefer documents where multiple terms appear in the priority index.
