message: subscriber: fix broken docs links in `MakeWriter`
  This fixes a few broken rustdoc links in the `MakeWriter` and
  `MakeWriterExt` rustdocs.
diff: @@ -435,6 +435,8 @@ pub trait MakeWriterExt<'a>: MakeWriter<'a> {
  ///
  /// `and` can be used in conjunction with filtering combinators. For
  /// example, if we want to write to a number of outputs depending on
  + ///
  + /// [writers]: std::io::Write
  fn and<B>(self, other: B) -> Tee<Self, B>
  where
  Self: Sized,
  @@ -463,6 +465,8 @@ pub trait MakeWriterExt<'a>: MakeWriter<'a> {
  ///
  /// tracing_subscriber::fmt().with_writer(mk_writer).init();
  /// ```
  + ///
  + /// [`make_writer`]: MakeWriter::make_writer
  fn or_else<W, B>(self, other: B) -> OrElse<Self, B>
  where
  Self: MakeWriter<'a, Writer = OptionalWriter<W>> + Sized,
  @@ -594,7 +598,7 @@ pub struct WithMinLevel<M> {
  }
  /// A [`MakeWriter`] combinator that wraps a [`MakeWriter`] with a predicate for
  -/// span and event [`Metadata`], so that the [`MakeWriterExt::make_writer_for`]
  +/// span and event [`Metadata`], so that the [`MakeWriter::make_writer_for`]
  /// method returns [`OptionalWriter::some`] when the predicate returns `true`,
  /// and [`OptionalWriter::none`] when the predicate returns `false`.
  ///
  