Rust port includes dependency even with std

[Romacat2]

According to my observations, features "std" includes num-traits as a dependency

[features]
default = ["std"]
f64 = []
std = ["num-traits/std"]
libm = ["num-traits/libm"]

although in the code lib.rs:

// Use the `num-traits` crate's `Float` trait if the user has enabled the `libm` feature flag
#[cfg(feature = "libm")]
use num_traits::float::Float as FloatOps;

// Use the standard library's `f32` type for floating point math operators if we're in an `std` (not `no_std`) context and the user hasn't enabled the `libm` feature flag
#[cfg(all(feature = "std", not(feature = "libm")))]
use f32 as FloatOps;

num-traits is only used with the libm feature, as mentioned on the crates.io page.
To fix this problem, you need to replace

std = ["num-traits/std"]

with

std = []