Remove .dat, .mod and .run AMPL extensions as they are ambiguous
Remove .dat, .mod and .run AMPL extensions as they are ambiguous

As discussed in #2073 adding these extensions will require more work
to avoid incorrect language detection.
SRI-CSL/linguist,kyoungrok0517/linguist,a0viedo/linguist,alitalia/linguist,kr/linguist,osorgin/linguist,ppaulweber/github-linguist,pcantrell/linguist,georgesuperman/linguist,adamkaplan/linguist,yscho/linguist,seanders/linguist,jtbandes/linguist,steventhanna/linguist,FStarLang/linguist,anhongyue/test222,christop/linguist,whitj00/linguist,BerkeleyTrue/linguist,chiranjeevjain/linguist,mwpastore/linguist,github/linguist,github/linguist,Mx7f/linguist,thejameskyle/linguist,nburkley/linguist,stanhu/linguist,JJ/linguist,meunierfrederic/octocatlinguist,hcutler/linguist,yyx990803/linguist,davidzchen/linguist,jjatria/linguist,PsichiX/linguist,pchaigno/linguist,hcutler/linguist,JJ/linguist,erkyrath/linguist,pcantrell/linguist,kr/linguist,CegepVictoriaville/linguist,osorgin/linguist,ppaulweber/github-linguist,mwpastore/linguist,MostAwesomeDude/linguist,github/linguist,manveru/linguist,mcandre/linguist,assimovt/ling-ist,yyx990803/linguist,steventhanna/linguist,pchaigno/linguist,cokeboL/linguist,scttnlsn/linguist,mcandre/linguist,pchaigno/linguist,scttnlsn/linguist,erkyrath/linguist,SRI-CSL/linguist,sagar290/linguist,manveru/linguist,sebgod/linguist,cokeboL/linguist,georgesuperman/linguist,nburkley/linguist,a0viedo/linguist,meunierfrederic/octocatlinguist,ilyes14/linguist,adamkaplan/linguist,thejameskyle/linguist,matt40k/linguist,erkyrath/linguist,douglas-larocca/linguist,bluebear94/linguist,tschf/linguist,JJ/linguist,pchaigno/linguist,ilyes14/linguist,chiranjeevjain/linguist,Mx7f/linguist,ya7lelkom/linguist,BerkeleyTrue/linguist,FStarLang/linguist,c-lipka/linguist,sebgod/linguist,martynbm/linguist,christop/linguist,MadcapJake/linguist,bluebear94/linguist,JJ/linguist,sagar290/linguist,jtbandes/linguist,c-lipka/linguist,mattn/linguist,kyoungrok0517/linguist,yyx990803/linguist,yscho/linguist,CegepVictoriaville/linguist,stanhu/linguist,ammaraskar/linguist,hcatlin/linguist,github/linguist,MostAwesomeDude/linguist,anhongyue/test222,martynbm/linguist,R4PaSs/linguist,MahmoudFayed/linguist,mattn/linguist,jrnold/linguist,seanders/linguist,stanhu/linguist,iblech/linguist,CoderXpert/linguist,iblech/linguist,R4PaSs/linguist,sebgod/linguist,douglas-larocca/linguist,PsichiX/linguist,cybernet14/linguist,yyx990803/linguist,tschf/linguist,phpsgi/linguist,jrnold/linguist,MahmoudFayed/linguist,MadcapJake/linguist,alitalia/linguist,assimovt/ling-ist,erkyrath/linguist,matt40k/linguist,cybernet14/linguist,ya7lelkom/linguist,sebgod/linguist,CoderXpert/linguist,whitj00/linguist,meunierfrederic/octocatlinguist,jjatria/linguist,hcatlin/linguist,phpsgi/linguist,ammaraskar/linguist,stanhu/linguist,davidzchen/linguist