Update tracing-subscriber/src/fmt/writer.rs

Co-authored-by: Josh McKinney <joshka@users.noreply.github.com>

Author: d-e-s-o

tracing-subscriber/src/fmt/writer.rs

@@ -496,7 +496,7 @@ pub struct MutexGuardWriter<'a, W>(MutexGuard<'a, W>);
 /// `TestWriter` is used by [`fmt::Collector`] or [`fmt::Subscriber`] to enable capturing support.
 ///
 /// `cargo test` can only capture output from the standard library's [`print!`] and [`eprint!`]
-/// macros. See [`libtest`'s output capturing][capturing] for more details about output capturing.
+/// macros. See [`libtest`'s output capturing][capturing] and [rust-lang/rust#90785](https://github.com/rust-lang/rust/issues/90785) for more details about output capturing.
 ///
 /// Writing to [`io::stdout`] and [`io::stderr`] produces the same results as using
 /// [`libtest`'s `--nocapture` option][nocapture] which may make the results look unreadable.