Idea: optional entity-level hunk labels (which function/class changed) via sem

[rs545837]

delta already shows a hunk's function context from git's @@ header, which is a heuristic. Would there be interest in optional, accurate entity labels, showing precisely which function/class/method each change belongs to and whether it was added, modified, or removed?

This could be backed by sem, an open-source (MIT/Apache) entity-level code tool written in Rust. It resolves entities across 26 languages via tree-sitter and exposes a sem-core crate, so for a Rust project like delta it can integrate as a library rather than a subprocess (there's also a JSON CLI: sem diff --patch --format json).

Concretely it could power a precise "in function foo" / "modified method Bar::baz" label per hunk, or a short per-file semantic summary above the diff.

I maintain sem and would be happy to prototype this if there's appetite. Curious whether it fits delta's scope or is better as an external integration.