Description ignored on enums
### Summary

Description on enum not copied from SQL comment to gql schema 

### Steps to reproduce

```
create type
e as enum('A', 'B');

comment on
type e is E'@name F
G';

create table t(c e);
```

### Expected results

```
"""G"""
enum F {
  A
  B
}
```

### Actual results

```
enum F {
  A
  B
}
```

### Additional context

Graphile @ 3df4bc53de8210c11223cf03a27646374240b8ec

