rust: alloc: use kernel::fmt

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

This backslid in commit 9def0d0 ("rust: alloc: add
Vec::push_within_capacity").

Reviewed-by: Alice Ryhl <[email protected]>
Acked-by: Danilo Krummrich <[email protected]>
Signed-off-by: Tamir Duberstein <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

Author: tamird

rust/kernel/alloc/kvec/errors.rs

@@ -2,14 +2,14 @@
 
 //! Errors for the [`Vec`] type.
 
-use kernel::fmt::{self, Debug, Formatter};
+use kernel::fmt;
 use kernel::prelude::*;
 
 /// Error type for [`Vec::push_within_capacity`].
 pub struct PushError<T>(pub T);
 
-impl<T> Debug for PushError<T> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+impl<T> fmt::Debug for PushError<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "Not enough capacity")
     }
 }
@@ -25,8 +25,8 @@ impl<T> From<PushError<T>> for Error {
 /// Error type for [`Vec::remove`].
 pub struct RemoveError;
 
-impl Debug for RemoveError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+impl fmt::Debug for RemoveError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "Index out of bounds")
     }
 }
@@ -45,8 +45,8 @@ pub enum InsertError<T> {
     OutOfCapacity(T),
 }
 
-impl<T> Debug for InsertError<T> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+impl<T> fmt::Debug for InsertError<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             InsertError::IndexOutOfBounds(_) => write!(f, "Index out of bounds"),
             InsertError::OutOfCapacity(_) => write!(f, "Not enough capacity"),