Add fmt::Binary constraint to BitFlagNum

Otherwise, `T: Debug` isn't enough to imply `BitFlags<T>: Debug`, and
this can get in the way of code generated by #[derive(Debug)].

Author: arcnmx

enumflags/src/formatting.rs

@@ -4,7 +4,7 @@ use crate::{BitFlags, _internal::RawBitFlags};
 impl<T> fmt::Debug for BitFlags<T>
 where
     T: RawBitFlags + fmt::Debug,
-    T::Type: fmt::Binary + fmt::Debug,
+    T::Type: fmt::Debug,
 {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         let name = T::bitflags_type_name();

enumflags/src/lib.rs

@@ -89,6 +89,7 @@ pub mod _internal {
 
     use core::ops::{BitAnd, BitOr, BitXor, Not};
     use core::cmp::PartialOrd;
+    use core::fmt;
 
     pub trait BitFlagNum
         : Default
@@ -97,6 +98,7 @@ pub mod _internal {
         + BitXor<Self, Output = Self>
         + Not<Output = Self>
         + PartialOrd<Self>
+        + fmt::Binary
         + Copy
         + Clone {
     }