Precise context: Heuristically match Syntect and SCIP symbol names

[efritz]

In one way to combat over-fetching, we'll want to ensure that we don't fetch imprecise SCIP names when ambiguous results come back. We should further prune candidates from the database by looking at edit distance/jaccard index or some other heuristic to throw out likely imprecise suffix matches.

[varungandhi-src]

For syntactic indexing, we also need approximate symbol matching. Closing this for now as unscoped.

• https://github.com/sourcegraph/sourcegraph/issues/58727