Ignore dead_code warning in test

    warning: method `try_into_tokens` is never used
      --> tests/macros/mod.rs:78:8
       |
    77 | pub trait TryIntoTokens {
       |           ------------- method in this trait
    78 |     fn try_into_tokens(self) -> Result<proc_macro2::TokenStream>;
       |        ^^^^^^^^^^^^^^^
       |
       = note: `#[warn(dead_code)]` on by default

tests/macros/mod.rs

@@ -75,6 +75,7 @@ macro_rules! snapshot_impl {
 }
 
 pub trait TryIntoTokens {
+    #[allow(dead_code)]
     fn try_into_tokens(self) -> Result<proc_macro2::TokenStream>;
 }