merge development.md

Author: ss2165

DEVELOPMENT.md

@@ -32,6 +32,9 @@ To setup the environment manually you will need:
 - Rust `>=1.75`: https://www.rust-lang.org/tools/install
 - uv `>=0.3`: docs.astral.sh/uv/getting-started/installation
 - capnproto `>=1.0`: https://capnproto.org/install.html
+- Optional: llvm `== 14.0`. The "llvm" feature (backed by the sub-crate `hugr-llvm`)
+  requires LLVM installed. We use the rust bindings
+[llvm-sys](https://crates.io/crates/llvm-sys) to [llvm](https://llvm.org/),
 
 Once you have these installed, you can install the required python dependencies and setup pre-commit hooks with: