This is following `hashbrown`'s switch in v0.15 from ahash to foldhash
for its `default-haster` feature, applied only to helix-event for now.
I don't have a strong preference between the two. Benchmarks in
Spellbook, which is particularly sensitive to hashers and hash table
performance, show no perceptible difference. Foldhash is dependency-free
though.
Once we migrate to the new tree-sitter bindings and highlighter we
should be able to eliminate the remaining dependencies on ahash.
82f07fe6d1