[rust] allow unused-macro-rules to unblock toolchain roll

Bug: 100318
Change-Id: Ided9428282c66e63cda934a5f456223750703179
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/679506
Reviewed-by: Joseph Ryan <[email protected]>
Fuchsia-Auto-Submit: Dan Johnson <[email protected]>
Reviewed-by: Tyler Mandry <[email protected]>
Commit-Queue: Auto-Submit <[email protected]>

Author: ComputerDruid

src/lib/storage/vfs/rust/src/path.rs

@@ -182,6 +182,8 @@ impl AsRef<str> for Path {
 mod tests {
     use super::*;
 
+    #[allow(unknown_lints)] // TODO(fxbug.dev/99424): remove this after toolchain roll when lint is known
+    #[allow(unused_macro_rules)] // TODO(fxbug.dev/100318): remove unused macro rules and re-enable
     macro_rules! simple_construction_test {
         (path: $str:expr, $path:ident => $body:block) => {
             match Path::validate_and_split($str) {