[libc++] NFC: Normalize `#endif //` comment indentation

GitOrigin-RevId: 4cd6ca102a94e1b64ba3f940cc26b4d7b2b82964
diff --git a/include/stdexcept b/include/stdexcept
index 7b5de7e..8eb7280 100644
--- a/include/stdexcept
+++ b/include/stdexcept
@@ -306,4 +306,4 @@
 
 _LIBCPP_END_NAMESPACE_STD
 
-#endif  // _LIBCPP_STDEXCEPT
+#endif // _LIBCPP_STDEXCEPT