Update AUTHORS.md to document Rust bindings heritage

Signed-off-by: Till Schneidereit <till@tillschneidereit.net>

Author: tschneidereit

AUTHORS.md

@@ -2,4 +2,8 @@ The portions of this code found in the initial commit are Copyright © 2021-2023
 contributors to Fastly's
 [js-compute-runtime project](https://github.com/fastly/js-compute-runtime/).
 
-Changes following that initial commit are Copyright © the respective contributors.
+Changes following that initial commit are Copyright © the respective contributors where not documented otherwise.
+
+## Rust Bindings
+
+The Rust bindings found under [runtime/crates](runtime/crates) are based on the Servo project's [mozjs and mozjs-sys](https://github.com/servo/mozjs) crates. The code under that folder is Copyright © The Servo Project Developers up to the fork, and Copyright © the respective contributors where not documented otherwise from then on.