[RFC]: Support for completion

[ulisses-cruz]

Reason

To be able to, easily explore the GraphQL endpoints with the plugin.

How would it work

Probably with the help of completion plugins.

For example, it is not difficult to create a nvim-cmp source.

Also, GraphQL provides introspection, which other clients use to know what attributes to used in the current scope.

This video can also be of help.

Future?

These are only ideas for now. But the same point above could be used to create a docs for the GraphQL endpoint.
But in that case, we should probably allow only one endpoint per file?!