Bug on enum value descriptions

Using descriptions on enum values is not working.

This schema makes AppSync schema parser going crazy

```graphql
# Represents the individual results of a search.
enum SearchType {
# Returns results matching objects.
OBJECT
# Returns results matching users.
USER
}
```

Gives:


I'm forced to remove all enum value descriptions in my schema...

```graphql
# Represents the individual results of a search.
enum SearchType {
OBJECT
USER
}
```

Is there any workaround to set description on enum values?

Maybe related to:
- https://github.com/aws/aws-appsync-community/issues/38

Start by reproducing the SearchType schema in the AppSync schema parser and compare it with the version without enum value descriptions. Read the related issue #38 for context; done means enum value descriptions are accepted without the parser failure, or a documented workaround is provided.

Written by the indexing model from the issue text.