Clarify and expand on HologramDash functions.
Clarify and expand on HologramDash functions.

Summary:
Fixes T2741
Reworded casual second person point-of-view.
Added some example code for clarification.

Test Plan: Review comments/changes

Reviewers: reuben, zheng, phogan, matt

Reviewed By: matt

Maniphest Tasks: T2741

Differential Revision: https://phabricator.knkdt.com/D1461

hologram-io/docs,hologram-io/docs