Merge #600

600: make GeoFloat: + Debug r=frewsxcv a=michaelkirk

- [x] I agree to follow the project's [code of conduct](https://github.com/georust/geo/blob/master/CODE_OF_CONDUCT.md).
- [x] I added an entry to `CHANGES.md` if knowledge of this change could be valuable to users.
---

This would be a breaking change, but `GeoFloat` hasn't been released yet.


Co-authored-by: Michael Kirk <michael.code@endoftheworl.de>

geo/src/lib.rs

@@ -152,5 +152,11 @@ pub mod prelude {
 ///     })
 /// }
 /// ```
-pub trait GeoFloat: num_traits::Float + CoordinateType + algorithm::kernels::HasKernel {}
-impl<T> GeoFloat for T where T: num_traits::Float + CoordinateType + algorithm::kernels::HasKernel {}
+pub trait GeoFloat:
+    num_traits::Float + CoordinateType + algorithm::kernels::HasKernel + std::fmt::Debug
+{
+}
+impl<T> GeoFloat for T where
+    T: num_traits::Float + CoordinateType + algorithm::kernels::HasKernel + std::fmt::Debug
+{
+}