brew-config: remove recommended compiler versions
brew-config: remove recommended compiler versions

The recommended compiler versions printed from `brew-config` are out
of date and misleading. The recommendation is always "Run the latest
version of Xcode available for your platform".

staticfloat/brew,vitorgalvao/brew,hanxue/linuxbrew,alyssais/brew,maxim-belkin/brew,EricFromCanada/brew,MikeMcQuaid/brew,bfontaine/brew,jmsundar/brew,gregory-nisbet/brew,EricFromCanada/brew,claui/brew,konqui/brew,hanxue/linuxbrew,MikeMcQuaid/brew,MikeMcQuaid/brew,palxex/brew,Linuxbrew/brew,toonetown/homebrew,Linuxbrew/brew,reelsense/brew,toonetown/homebrew,hanxue/linuxbrew,vitorgalvao/brew,bfontaine/brew,Homebrew/brew,palxex/brew,konqui/brew,amar-laksh/brew_sudo,palxex/brew,muellermartin/dist,muellermartin/dist,nandub/brew,pseudocody/brew,staticfloat/brew,claui/brew,reelsense/brew,JCount/brew,zmwangx/brew,Homebrew/brew,pseudocody/brew,DomT4/brew,reitermarkus/brew,ilovezfs/brew,mgrimes/brew,muellermartin/dist,gregory-nisbet/brew,sjackman/homebrew,rwhogg/brew,DomT4/brew,vitorgalvao/brew,reelsense/brew,aw1621107/brew,rwhogg/brew,mistydemeo/homebrew,mgrimes/brew,mahori/brew,gordonmcshane/homebrew,pseudocody/brew,AnastasiaSulyagina/brew,alyssais/brew,ilovezfs/brew,staticfloat/brew,claui/brew,tonyg/homebrew,jmsundar/brew,Homebrew/brew,gordonmcshane/homebrew,amar-laksh/brew_sudo,tonyg/homebrew,zmwangx/brew,sjackman/homebrew,JCount/brew,zmwangx/brew,Homebrew/brew,reitermarkus/brew,EricFromCanada/brew,nandub/brew,DomT4/brew,gregory-nisbet/brew,amar-laksh/brew_sudo,vitorgalvao/brew,DomT4/brew,MikeMcQuaid/brew,ilovezfs/brew,mahori/brew,mgrimes/brew,claui/brew,mistydemeo/homebrew,AnastasiaSulyagina/brew,nandub/brew,maxim-belkin/brew,jmsundar/brew,alyssais/brew,konqui/brew,sjackman/homebrew,Linuxbrew/brew,JCount/brew,tonyg/homebrew,Linuxbrew/brew,toonetown/homebrew,EricFromCanada/brew,mistydemeo/homebrew,nandub/brew,aw1621107/brew,konqui/brew,AnastasiaSulyagina/brew,bfontaine/brew,maxim-belkin/brew,rwhogg/brew,gordonmcshane/homebrew,reitermarkus/brew,aw1621107/brew,sjackman/homebrew,JCount/brew,mahori/brew,mahori/brew,reitermarkus/brew