[Educator] How to: Add links to other sections of the course

[jmakowski1123]

Source, possible marketing video: https://docs.google.com/spreadsheets/d/1m1zTyiIDYkDI79AgGw_JNeWi1hkIZptRUbwirgPnPJQ/edit#gid=1843368591

[jswope00]

Included here: https://docs.openedx.org/en/latest/educators/how-tos/course_development/text_components/manage_text.html#add-a-link-to-a-course-unit