Fix suggestion text for -debug= dflags. See #310.
Fix suggestion text for -debug= dflags. See #310.

alexeibs/dub,xentec/dub,Geod24/dub,jelmansouri/dub,Abscissa/dub,y12uc231/dub,schuetzm/dub,rjframe/dub,Abscissa/dub-data-mod,jeanbaptistelab/dub,gedaiu/dub,dreamsxin/dub,p0nce/dub,nazriel/dub,D-Programming-Language/dub,Flamaros/dub,grogancolin/dub