How can I show C++ code documentation in Xcode 9.3?

Question

I´m developing software based on C++ in Xcode and want to have (at least) the same convenience for code documentation as if I was developing for Swift or objc.

Exam

Answer 1

I'll upvote Deb's answer but I was also looking at this for a little while.

Markdown in Xcode is somewhat brittle in Xcode 9.

It works for function declarations:

And also for callouts:

Documentation comments seems to work well for function declarations, but doesn't work at all for lines of code within the functions.