refactor: autofix issues in 2 files

Resolved issues in the following files with DeepSource Autofix:
1. concat/__main__.py
2. concat/stdlib/repl.py

concat/__main__.py

@@ -128,6 +128,6 @@ def create_parsing_failure_message(
             import_resolution_start_directory=source_dir,
         )
         if list(concat_ast.parsing_failures):
-            exit(1)
+            sys.exit(1)
     finally:
         args.file.close()

concat/stdlib/repl.py

@@ -123,7 +123,7 @@ def read_quot(
 def _exit_repl() -> NoReturn:
     print_exit_message()
     # TODO: Don't exit the whole program because we can nest REPLs.
-    exit()
+    sys.exit()
 
 
 def print_exit_message() -> None: