doxygen-vs-LaTeX issue

@karl-wette after making the first fix to the "LALPulsar Header ComputeFstat.h" page (current public version) in !2057 (merged) (version built from that), it still doesn't show the detailed documentation of most functions (including in/out argument explanations and "Definition at line X" comments). I've tracked this down to LaTeX usage: Apparently having things like \f$\mathcal{F}\f$ in the initial comment block for a function is fine, but if it appears in the in/out argument annotations, it breaks the parsing of that function and of all other functions coming below it in the ComputeFstat.c file. Hence, the dfreq comment on XLALCreateFstatInput() is the first culprit.

I suspect this is down to comment marker style, since some other source files use in/out LaTeX annotations successfully, e.g. LineRobustStats.c -> complete output.

I've tried changing the ComputeFstat.c in/out annotations from ///< to the //!< as in the other module, but that didn't help. Any ideas?