CONTRIBUTING: clarifications and cleanup.
CONTRIBUTING: clarifications and cleanup.

Closes Homebrew/homebrew#48857.

Signed-off-by: Mike McQuaid <a17fed27eaa842282862ff7c1b9c8395a26ac320@mikemcquaid.com>

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