Allow sorting only top level declarations in schema

[kbrooks]

Is your feature request related to a problem? Please describe.

This library is a dependency of graphql-code-generator which is used to produce a generated schema file.

dotansimha/graphql-code-generator#6935

I opened an issue on graphql-js here graphql/graphql-js#3971 but it was closed due to there being a trivial work-around. We can use this approach in this library to resolve my issue.

Describe the solution you'd like

Add a field to the options on loadSchemaSync which enables sorting only the top level declarations

    return options.sort
       ? lexicographicSortSchema(sources[0].schema) 
       : options.sortShallow // naming?
       ? shallowSortSchema(sources[0].schema) 
       : sources[0].schema;

...

function shallowSortSchema(schema) {
  const schemaConfig = schema.toConfig();
  const sortedSchema = new GraphQLSchema({
    ...schemaConfig,
    types: [...schemaConfig.types].sort((a, b) => a.name.localeCompare(b.name)),
  });
}

I can prepare a PR for this myself.

Describe alternatives you've considered

Currently I am applying a patch to the graphql-js lexicographicSortSchema function in order to produce my desired output.

Additional context

[erwan-joly]

Facing the same issue so would love to see this :)