Episode 3.4 todo notes visible to learners

[SJaffa]

python-intermediate-development/episodes/34-code-refactoring.md

Lines 332 to 333 in 3035eaf

	* Doing simulations (? needs more explanation)
	* Translating data from one format to another (? an example would be good)

Could we make the "(?..)" notes not visible in the learner view, or not visible in the rendered view at all?