extend/string: backport #rpartition
extend/string: backport #rpartition

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