fixed nostd issues

Author: piedoom

crates/firewheel-core/src/dsp/delay_line.rs

@@ -1,6 +1,8 @@
 use core::num::NonZeroU32;
 
 use bevy_platform::prelude::Vec;
+#[cfg(not(feature = "std"))]
+use num_traits::Float;
 
 #[derive(Debug)]
 pub struct DelayLine {

crates/firewheel-nodes/src/echo.rs

@@ -24,6 +24,8 @@ use firewheel_core::{
     },
     param::smoother::{SmoothedParam, SmootherConfig},
 };
+#[cfg(not(feature = "std"))]
+use num_traits::Float;
 
 const DEFAULT_DELAY_SMOOTH_SECONDS: f32 = 0.25;