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

GitOrigin-RevId: 4cd6ca102a94e1b64ba3f940cc26b4d7b2b82964
diff --git a/include/__debug b/include/__debug
index 7b5bfb3..771e431 100644
--- a/include/__debug
+++ b/include/__debug
@@ -270,4 +270,4 @@
 
 _LIBCPP_END_NAMESPACE_STD
 
-#endif  // _LIBCPP_DEBUG_H
+#endif // _LIBCPP_DEBUG_H