Compilation warning on Elixir 1.20+ due to stricter `__STACKTRACE__` type inference

[chgeuer]

Elixir 1.20.0-rc.1 introduced stricter type inference for __STACKTRACE__. This causes a "clause will never match" warning in lib/zig/error_prong.ex when pattern matching on the stacktrace structure.

The compiler infers a strict type for __STACKTRACE__ which conflicts with the pattern [{_m, _f, a, _}, {m, f, _a, opts} | rest] used in argument_error_prong/3 and return_error_prong/4, specifically regarding the type of opts.

This breaks CI/CD pipelines that treat warnings as errors.