Implement Display for meta::Integer and meta::Float

Those impls is pretty unambiguous I think.

src/meta.rs

@@ -1,6 +1,8 @@
 //! Types for [`Config::META`][super::Config::META]. Represent information about
 //! a configuration type.
 
+use core::fmt;
+
 // TODO: having all these fields public make me uncomfortable. For now it's
 // fine, but before reaching 1.0 I need to figure out how to allow future
 // additions without breaking stuff.
@@ -63,3 +65,32 @@ pub enum Integer {
     I128(i128),
     Isize(isize),
 }
+
+
+impl fmt::Display for Float {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::F32(v) => v.fmt(f),
+            Self::F64(v) => v.fmt(f),
+        }
+    }
+}
+
+impl fmt::Display for Integer {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::U8(i) => i.fmt(f),
+            Self::U16(i) => i.fmt(f),
+            Self::U32(i) => i.fmt(f),
+            Self::U64(i) => i.fmt(f),
+            Self::U128(i) => i.fmt(f),
+            Self::Usize(i) => i.fmt(f),
+            Self::I8(i) => i.fmt(f),
+            Self::I16(i) => i.fmt(f),
+            Self::I32(i) => i.fmt(f),
+            Self::I64(i) => i.fmt(f),
+            Self::I128(i) => i.fmt(f),
+            Self::Isize(i) => i.fmt(f),
+        }
+    }
+}