Fix docs:graphql:generate

[BlairCurrey]

Currently the documentation docs:graphql:generate points to the wrong directory (should be api-reference instead of reference). Additionally, we should add a CI step to check if anything was generated and fail if so. Similar to our graphql check:

rafiki/.github/workflows/lint_test_build.yml

Lines 21 to 42 in 7a3078c

	graphql:
	runs-on: ubuntu-22.04
	needs: checkout
	steps:
	- uses: actions/checkout@v3
	- uses: ./.github/workflows/rafiki/env-setup
	- name: generate backend graphql
	run: pnpm --filter backend generate
	- name: generate auth graphql
	run: pnpm --filter auth generate
	- name: verify changed files
	uses: tj-actions/verify-changed-files@v14
	id: verify-changed-files
	with:
	files: |
	**/generated/graphql.*
	- name: fail if GraphQL was generated
	if: steps.verify-changed-files.outputs.files_changed == 'true'
	run: exit 1