index.md
	concepts/index.md
		concepts/yaml_format.md
	tutorial/index.md
		tutorial/install.md
		tutorial/ingester.md
			tutorial/ingester-full-code.md
	tools.md
	modules.md
		modules/window.md
	mf-index

index.md
	concepts/index.md
		modules.md
			modules/window.md
		concepts/yaml_format.md
	tutorial/index.md
		tutorial/install.md
		tutorial/ingester.md
			tutorial/ingester-full-code.md
	tools.md
	mf-index

Move modules section under concepts
docs: Move modules section under concepts

https://phabricator.endlessm.com/T21249
