bin/brew: rename 'chdir' to 'quiet_cd'
bin/brew: rename 'chdir' to 'quiet_cd'

This is inspired by `quiet_system` with basically the same implication
(suppress output), making the name a lot less confusing and avoiding a
clash with the `chdir` function defined in `Library/brew.sh`.

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