Remove the unused bounds from Debug impl of HashMap::{IntoKeys,IntoValues}

Author: canova

library/std/src/collections/hash/map.rs

@@ -1915,7 +1915,7 @@ impl<K, V> ExactSizeIterator for IntoKeys<K, V> {
 impl<K, V> FusedIterator for IntoKeys<K, V> {}
 
 #[unstable(feature = "map_into_keys_values", issue = "75294")]
-impl<K: Debug, V: Debug> fmt::Debug for IntoKeys<K, V> {
+impl<K: Debug, V> fmt::Debug for IntoKeys<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.inner.iter().map(|(k, _)| k)).finish()
     }
@@ -1945,7 +1945,7 @@ impl<K, V> ExactSizeIterator for IntoValues<K, V> {
 impl<K, V> FusedIterator for IntoValues<K, V> {}
 
 #[unstable(feature = "map_into_keys_values", issue = "75294")]
-impl<K: Debug, V: Debug> fmt::Debug for IntoValues<K, V> {
+impl<K, V: Debug> fmt::Debug for IntoValues<K, V> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.inner.iter().map(|(_, v)| v)).finish()
     }