Fix menu position of the labels-custom-metadata.md topic

Signed-off-by: Misty Stanley-Jones <misty@docker.com>

docs/userguide/labels-custom-metadata.md

@@ -4,8 +4,8 @@ title = "Managing Docker object labels"
 description = "Description of labels, which are used to manage metadata on Docker objects."
 keywords = ["Usage, user guide, labels, metadata, docker, documentation, examples, annotating"]
 [menu.main]
-parent = "engine_guide_intro"
-weight=90
+parent = "engine_guide"
+weight=100
 +++
 <![end-metadata]-->