Fix fmt issue on trunk (#2810)

Summary:
Fix CI issue on trunk due to fmt issues

Pull Request resolved: #2810

Test Plan: `cargo fmt`

Reviewed By: rchen152

Differential Revision: D96842582

Pulled By: fangyi-zhou

fbshipit-source-id: 997b4cf91704006f66e01e426b7cb17c6c5a9b68

Author: fangyi-zhou

pyrefly/lib/stubgen/mod.rs

@@ -27,10 +27,13 @@ mod tests {
     use crate::test::util::TestEnv;
 
     fn run_stubgen(input: &str) -> String {
-        run_stubgen_with_config(input, &ExtractConfig {
-            include_private: false,
-            include_docstrings: false,
-        })
+        run_stubgen_with_config(
+            input,
+            &ExtractConfig {
+                include_private: false,
+                include_docstrings: false,
+            },
+        )
     }
 
     fn run_stubgen_with_config(input: &str, config: &ExtractConfig) -> String {
@@ -107,10 +110,10 @@ mod tests {
         let expected = fs_anyhow::read_to_string(&expected_path)
             .unwrap()
             .replace("\r\n", "\n");
-        // Strip the @generated header and trim whitespace so the expected
+        // Strip the AT generated header and trim whitespace so the expected
         // files can keep the header for tooling without affecting comparison.
         let expected = expected
-            .strip_prefix("# @generated\n")
+            .strip_prefix(&format!("# @{}generated\n", "")) // Avoid this file from being recognized as generated
             .unwrap_or(&expected)
             .trim()
             .to_owned();