In DMG p.139 Scrolls are listed under Magic Item Categories:
The most prevalent type of scroll is the spell scroll (...). A scroll is a consumable magic item.
PHB p.231 mentions about Detect Magic:
For the duration [of 10 minutes], you sense the presence of magic within 30 feet of you. If you sense magic in this way, you can use your action to see a faint aura around any visible creature or object in the area that bears magic, and you learn its school of magic, if any.
The spell can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.
Yes, using this spell enables you to sense spell scrolls in the vicinity.
It's unclear to me why that Roll20 compendium would contradict the information in the DMG. EDIT: See comments by Icyfire in the question for a clarification.