Glitches in the Documentation

[ricejasonf]

Many of the Concepts associated functions are either missing, misnamed, or just weird.

For example Monad does not show flatten or chain in the submenu.

Also ap is named just A.

Most amusingly there is a new function called mathrm in MonadPlus. 🤣
http://boostorg.github.io/hana/group__group-_monad_plus.html#ga5ee54dc1195f9e5cf48bfd51ba231ae5
(I think this was remove_if)

I have not yet looked to see what is causing this.

[ldionne]

Doxygen is broken. TBH I'm not sure what the solution would be short of rewriting the documentation using another tool.. that's kind of messed up.

[beojan]

Standardese might be an option. It looks like it can support LaTeX in comments (using MathJax): standardese/standardese#53.