Bogus "Unrecognized user attribute: __Enforceable starts with __ but is not a standard attribute" error

**Describe the bug**

__Enforceable is a standard attribute. The error saying it is not one is wrong.

**Standalone code, or other way to reproduce the problem**

```hack
<<__Enforceable>>
type Foo = string;
```

```
$ hh_client
```

**Expected behavior**

```
Typing[4231] The __Enforceable attribute cannot be used on a typealias.
--> test.hack
1 | <<__Enforceable>>
| ^^^^^^^^^^^^^
```

**Actual behavior**

```
Naming[2049] Unrecognized user attribute: __Enforceable starts with __ but is not a standard attribute
--> test.hack
1 | <<__Enforceable>>
| ^^^^^^^^^^^^^

Typing[4231] The __Enforceable attribute cannot be used on a typealias.
--> test.hack
1 | <<__Enforceable>>
| ^^^^^^^^^^^^^
```

This is on 4.48.1