* Add built-in gql function

* Add inner document source to DocumentNodes from gql

* Update tests to use new gql helper

* Protect against invalid inputs in gql

* Fix up execute tests

* Fix linting issues in gql.ts

* Add basic tests for gql tag

* Shave some bytes off of cacheExchange

* Simplify composeExchanges helper

* Replace all usages of graphql-tag

* Update entries in docs

* Add changeset

* Revert changes / Update snapshot

* Fix linting issues in populate and core

* Add core / gql section to Queries page