Ignore buggy nonstandard_macro_braces clippy lint

Clippy bug: rust-lang/rust-clippy#7422

    error: use of irregular braces for `format_args!` macro
     --> tests/test.rs:8:30
      |
    8 |     #[derive(Serialize_repr, Deserialize_repr, PartialEq, Debug)]
      |                              ^^^^^^^^^^^^^^^^
      |
      = note: `-D clippy::nonstandard-macro-braces` implied by `-D clippy::all`
    help: consider writing `Deserialize_repr`
     --> tests/test.rs:8:30
      |
    8 |     #[derive(Serialize_repr, Deserialize_repr, PartialEq, Debug)]
      |                              ^^^^^^^^^^^^^^^^
      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonstandard_macro_braces
      = note: this error originates in the derive macro `Deserialize_repr` (in Nightly builds, run with -Z macro-backtrace for more info)

    error: use of irregular braces for `format_args!` macro
      --> tests/test.rs:56:30
       |
    56 |     #[derive(Serialize_repr, Deserialize_repr, PartialEq, Debug)]
       |                              ^^^^^^^^^^^^^^^^
       |
    help: consider writing `Deserialize_repr`
      --> tests/test.rs:56:30
       |
    56 |     #[derive(Serialize_repr, Deserialize_repr, PartialEq, Debug)]
       |                              ^^^^^^^^^^^^^^^^
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonstandard_macro_braces
       = note: this error originates in the derive macro `Deserialize_repr` (in Nightly builds, run with -Z macro-backtrace for more info)

tests/test.rs

@@ -1,4 +1,8 @@
-#![allow(clippy::wildcard_imports)]
+#![allow(
+    // Clippy bug: https://github.com/rust-lang/rust-clippy/issues/7422
+    clippy::nonstandard_macro_braces,
+    clippy::wildcard_imports,
+)]
 
 use serde_repr::{Deserialize_repr, Serialize_repr};