Remove needless corpus path borrow

Fixes the clippy::needless_borrows_for_generic_args lint error reported by Clippy 1.98.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: aaf47101-2cb9-4d38-9f6a-e492c4da4135

Author: paldepind

unified/extractor/tests/corpus_tests.rs

@@ -123,7 +123,7 @@ fn test_corpus() {
         let output_schema = yeast::node_types_yaml::schema_from_yaml(languages::OUTPUT_AST_SCHEMA)
             .expect("Failed to parse OUTPUT_AST_SCHEMA YAML");
 
-        let lang_corpus_dir = corpus_dir.join(&lang.prefix);
+        let lang_corpus_dir = corpus_dir.join(lang.prefix);
         if !lang_corpus_dir.exists() {
             continue;
         }