Update xml docs on LanguageVersion (#22702)
Update xml docs on LanguageVersion (#22702)


diryboy/roslyn,tannergooding/roslyn,bartdesmet/roslyn,genlu/roslyn,heejaechang/roslyn,heejaechang/roslyn,VSadov/roslyn,dotnet/roslyn,davkean/roslyn,diryboy/roslyn,weltkante/roslyn,aelij/roslyn,dpoeschl/roslyn,sharwell/roslyn,Hosch250/roslyn,heejaechang/roslyn,MichalStrehovsky/roslyn,stephentoub/roslyn,xasx/roslyn,jamesqo/roslyn,paulvanbrenk/roslyn,khyperia/roslyn,jasonmalinowski/roslyn,gafter/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,mavasani/roslyn,DustinCampbell/roslyn,dpoeschl/roslyn,swaroop-sridhar/roslyn,tmeschter/roslyn,tmat/roslyn,lorcanmooney/roslyn,stephentoub/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,mattscheffer/roslyn,mattscheffer/roslyn,jmarolf/roslyn,AmadeusW/roslyn,KevinRansom/roslyn,eriawan/roslyn,eriawan/roslyn,OmarTawfik/roslyn,paulvanbrenk/roslyn,MichalStrehovsky/roslyn,Giftednewt/roslyn,brettfo/roslyn,tmeschter/roslyn,panopticoncentral/roslyn,orthoxerox/roslyn,orthoxerox/roslyn,orthoxerox/roslyn,abock/roslyn,KevinRansom/roslyn,bartdesmet/roslyn,jasonmalinowski/roslyn,OmarTawfik/roslyn,MichalStrehovsky/roslyn,jcouv/roslyn,physhi/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,bkoelman/roslyn,panopticoncentral/roslyn,paulvanbrenk/roslyn,KevinRansom/roslyn,khyperia/roslyn,nguerrera/roslyn,mattscheffer/roslyn,brettfo/roslyn,Hosch250/roslyn,ErikSchierboom/roslyn,jamesqo/roslyn,mmitche/roslyn,tannergooding/roslyn,weltkante/roslyn,cston/roslyn,wvdd007/roslyn,mavasani/roslyn,mmitche/roslyn,stephentoub/roslyn,tmat/roslyn,physhi/roslyn,shyamnamboodiripad/roslyn,mgoertz-msft/roslyn,davkean/roslyn,VSadov/roslyn,AmadeusW/roslyn,bkoelman/roslyn,KirillOsenkov/roslyn,DustinCampbell/roslyn,sharwell/roslyn,wvdd007/roslyn,reaction1989/roslyn,mmitche/roslyn,weltkante/roslyn,ErikSchierboom/roslyn,CyrusNajmabadi/roslyn,reaction1989/roslyn,Giftednewt/roslyn,Hosch250/roslyn,nguerrera/roslyn,panopticoncentral/roslyn,swaroop-sridhar/roslyn,KirillOsenkov/roslyn,shyamnamboodiripad/roslyn,pdelvo/roslyn,jcouv/roslyn,mavasani/roslyn,ErikSchierboom/roslyn,AlekseyTs/roslyn,sharwell/roslyn,abock/roslyn,dotnet/roslyn,reaction1989/roslyn,eriawan/roslyn,AlekseyTs/roslyn,aelij/roslyn,agocke/roslyn,CyrusNajmabadi/roslyn,jamesqo/roslyn,xasx/roslyn,OmarTawfik/roslyn,AmadeusW/roslyn,cston/roslyn,khyperia/roslyn,wvdd007/roslyn,nguerrera/roslyn,agocke/roslyn,diryboy/roslyn,shyamnamboodiripad/roslyn,tmat/roslyn,lorcanmooney/roslyn,swaroop-sridhar/roslyn,dpoeschl/roslyn,gafter/roslyn,mgoertz-msft/roslyn,pdelvo/roslyn,bartdesmet/roslyn,bkoelman/roslyn,jcouv/roslyn,davkean/roslyn,tannergooding/roslyn,mgoertz-msft/roslyn,genlu/roslyn,dotnet/roslyn,genlu/roslyn,brettfo/roslyn,gafter/roslyn,tmeschter/roslyn,physhi/roslyn,jmarolf/roslyn,jmarolf/roslyn,xasx/roslyn,KirillOsenkov/roslyn,DustinCampbell/roslyn,abock/roslyn,jasonmalinowski/roslyn,cston/roslyn,VSadov/roslyn,aelij/roslyn,CyrusNajmabadi/roslyn,agocke/roslyn,Giftednewt/roslyn,pdelvo/roslyn,AlekseyTs/roslyn,lorcanmooney/roslyn