Using \ingroup between \brief and the rest of the documentation causes
Doxygen to concatenate the brief with the rest of the doc.

* src/sanity/style.test: Warn when \ingroup is found
on the line after \brief.
* src/kripke/fairkripke.hh, src/kripke/kripke.hh,
src/kripke/kripkeprint.hh, src/ltlast/atomic_prop.hh,
src/ltlast/automatop.hh, src/ltlast/binop.hh, src/ltlast/bunop.hh,
src/ltlast/constant.hh, src/ltlast/formula.hh, src/ltlast/multop.hh,
src/ltlast/refformula.hh, src/ltlast/unop.hh, src/ltlast/visitor.hh,
src/ltlenv/declenv.hh, src/ltlenv/defaultenv.hh,
src/ltlenv/environment.hh, src/ltlparse/ltlfile.hh,
src/ltlvisit/clone.hh, src/ltlvisit/destroy.hh, src/ltlvisit/dotty.hh,
src/ltlvisit/dump.hh, src/ltlvisit/length.hh, src/ltlvisit/lunabbrev.hh,
src/ltlvisit/mark.hh, src/ltlvisit/nenoform.hh, src/ltlvisit/postfix.hh,
src/ltlvisit/randomltl.hh, src/ltlvisit/reduce.hh,
src/ltlvisit/relabel.hh, src/ltlvisit/simpfg.hh,
src/ltlvisit/simplify.hh, src/ltlvisit/tunabbrev.hh,
src/ltlvisit/wmunabbrev.hh, src/misc/bddalloc.hh, src/misc/bddlt.hh,
src/misc/freelist.hh, src/misc/hash.hh, src/misc/ltstr.hh,
src/misc/minato.hh, src/misc/modgray.hh, src/misc/optionmap.hh,
src/misc/version.hh, src/saba/explicitstateconjunction.hh,
src/saba/saba.hh, src/saba/sabacomplementtgba.hh, src/saba/sabastate.hh,
src/saba/sabasucciter.hh, src/sabaalgos/sabadotty.hh,
src/sabaalgos/sabareachiter.hh, src/ta/ta.hh, src/ta/taproduct.hh,
src/ta/tgta.hh, src/taalgos/reachiter.hh, src/taalgos/tgba2ta.hh,
src/tgba/futurecondcol.hh, src/tgba/sba.hh, src/tgba/state.hh,
src/tgba/succiter.hh, src/tgba/tgba.hh, src/tgba/tgbabddconcrete.hh,
src/tgba/tgbabddconcreteproduct.hh, src/tgba/tgbakvcomplement.hh,
src/tgba/tgbaproduct.hh, src/tgba/tgbasafracomplement.hh,
src/tgba/tgbascc.hh, src/tgba/tgbasgba.hh, src/tgba/tgbatba.hh,
src/tgba/tgbaunion.hh, src/tgba/wdbacomp.hh, src/tgbaalgos/bfssteps.hh,
src/tgbaalgos/degen.hh, src/tgbaalgos/dotty.hh,
src/tgbaalgos/dottydec.hh, src/tgbaalgos/dupexp.hh,
src/tgbaalgos/eltl2tgba_lacim.hh, src/tgbaalgos/lbtt.hh,
src/tgbaalgos/ltl2taa.hh, src/tgbaalgos/ltl2tgba_fm.hh,
src/tgbaalgos/ltl2tgba_lacim.hh, src/tgbaalgos/neverclaim.hh,
src/tgbaalgos/powerset.hh, src/tgbaalgos/projrun.hh,
src/tgbaalgos/randomgraph.hh, src/tgbaalgos/reachiter.hh,
src/tgbaalgos/reducerun.hh, src/tgbaalgos/replayrun.hh,
src/tgbaalgos/rundotdec.hh, src/tgbaalgos/save.hh,
src/tgbaalgos/stripacc.hh, src/tgbaalgos/translate.hh: Move \ingroup
before \brief.