[fix-ci-nightly] include Float / FloatCore for non-std builds for float_sampler

Author: rex-remind101

proptest/src/num/float_samplers.rs

@@ -21,6 +21,10 @@ macro_rules! float_sampler {
             use rand::distributions::uniform::{
                 SampleBorrow, SampleUniform, Uniform, UniformSampler,
             };
+            #[cfg(not(feature = "std"))]
+            use num_traits::float::FloatCore;
+            #[cfg(not(feature = "std"))]
+            use num_traits::float::Float;
 
             #[must_use]
             // Returns the previous float value. In other words the greatest value representable