test(bash_env_saved): fix type annotation

Author: akinomyoga

test/t/conftest.py

@@ -389,11 +389,12 @@ def assert_bash_exec(
 
 
 class bash_env_saved:
+
     def __init__(self, bash: pexpect.spawn, sendintr: bool = False):
         self.bash = bash
-        self.cwd = None
-        self.saved_shopt = {}
-        self.saved_variables = {}
+        self.cwd: Optional[str] = None
+        self.saved_shopt: Dict[str, int] = {}
+        self.saved_variables: Dict[str, int] = {}
         self.sendintr = sendintr
 
     def __enter__(self):
@@ -404,9 +405,9 @@ def __exit__(
         exc_type: Optional[Type[BaseException]],
         exc_value: Optional[BaseException],
         exc_traceback: Optional[TracebackType],
-    ) -> bool:
+    ) -> None:
         self._restore_env()
-        return False
+        return None
 
     def _copy_variable(self, src_var: str, dst_var: str):
         assert_bash_exec(