challenge named as discussion? #90
Description
Maybe we can replace the challenge tags which don't have a nested solution tag, with a discussion tag? (Refer: Different types of tags and corresponding blocks in the Workbench)
Also maybe avoid saying "Exercise: " in the header? Open to thoughts on it.
Example of an episode where challenge block does not have an associated solution block: https://imperialcollegelondon.github.io/rse_introductory_git_course/l3-02-guis-ides.html