Ignore buggy nonstandard_macro_braces clippy lint

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

    error: use of irregular braces for `write!` macro
      --> src/main.rs:68:10
       |
    68 | #[derive(Error, Debug)]
       |          ^^^^^
       |
       = note: `-D clippy::nonstandard-macro-braces` implied by `-D clippy::all`
    help: consider writing `Error`
      --> src/main.rs:68:10
       |
    68 | #[derive(Error, 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 `Error` (in Nightly builds, run with -Z macro-backtrace for more info)

src/main.rs

@@ -7,6 +7,8 @@
 #![allow(
     clippy::default_trait_access,
     clippy::let_underscore_drop,
+    // Clippy bug: https://github.com/rust-lang/rust-clippy/issues/7422
+    clippy::nonstandard_macro_braces,
     clippy::similar_names,
     clippy::single_match_else,
     clippy::too_many_lines,