Wording

Author: LegNeato

tests/difftests/README.md

@@ -148,7 +148,7 @@ config.write_metadata(&metadata)?;
 
 **Important notes:**
 
-- If no metadata file is written or the file is empty, the harness uses for exact byte
+- If no metadata file is written or the file is empty, the harness uses exact byte
   comparison.
 - All test packages must have consistent metadata. If packages specify different
   `output_type` values, the test will fail with an error.