I have begun making my code available on BitBucket but I want to include some sort of README or other documentation in each code repository I set up. When plain text doesn't meet my needs, I've been unsure what to turn to.
An interlocutor argued for Markdown, but in practice all that really means is trying to adhere to Markdown principles in my plain text — actually interpreting Markdown (as HTML, LaTeX, etc.) requires the user to have a separate application, something I can't assume.
Plain text will do for most cases, but more functionality is required when my README/doc needs math or tables. In the past I would have gone with HTML, but HTML now seems to be experiencing backward-incompatible growing pains and risks turning into Frankenstein. The competitor was PDF, which I had thought was proprietary but apparently I was wrong.