Trailing comments must be indicted with the caret //!<.
Not all places do this right now, see for example https://dev.visucore.com/bitcoin/doxygen/txmempool_8h.html#a2bc6653552b5871101b6cbefdbaf251f, but they can be fixed with an almost-scripted-diff:
0sed -i --regexp-extended -e 's/((,|;) *\/\/!) /\1< /g' $(git grep --extended-regexp -l '(,|;)\s*//!\s')
(Same as [doxygen] Fix member comments #7793)