audit: detect more 'pkgshare' candidates (#328)
audit: detect more 'pkgshare' candidates (#328)

The new check also allows the `+` operator instead of our (still heavily
preferred) `/` operator for path concatenation and also triggers if the
operator is surrounded by whitespace.

Also recognizes single-quoted strings and uses a back reference to
match the closing quote for a slightly lower chance of false positives.

Closes #322.
staticfloat/brew,bfontaine/brew,vitorgalvao/brew,toonetown/homebrew,tonyg/homebrew,aw1621107/brew,reitermarkus/brew,gregory-nisbet/brew,Linuxbrew/brew,Linuxbrew/brew,alyssais/brew,ilovezfs/brew,pseudocody/brew,zmwangx/brew,amar-laksh/brew_sudo,JCount/brew,DomT4/brew,reitermarkus/brew,reelsense/brew,gordonmcshane/homebrew,staticfloat/brew,sjackman/homebrew,mgrimes/brew,MikeMcQuaid/brew,rwhogg/brew,maxim-belkin/brew,ilovezfs/brew,hanxue/linuxbrew,nandub/brew,claui/brew,konqui/brew,mahori/brew,nandub/brew,maxim-belkin/brew,reelsense/brew,MikeMcQuaid/brew,hanxue/linuxbrew,alyssais/brew,sjackman/homebrew,konqui/brew,konqui/brew,pseudocody/brew,amar-laksh/brew_sudo,mahori/brew,gregory-nisbet/brew,alyssais/brew,vitorgalvao/brew,vitorgalvao/brew,muellermartin/dist,JCount/brew,Homebrew/brew,zmwangx/brew,staticfloat/brew,EricFromCanada/brew,sjackman/homebrew,jmsundar/brew,Linuxbrew/brew,pseudocody/brew,palxex/brew,aw1621107/brew,mahori/brew,DomT4/brew,gordonmcshane/homebrew,EricFromCanada/brew,DomT4/brew,Homebrew/brew,claui/brew,hanxue/linuxbrew,JCount/brew,reelsense/brew,toonetown/homebrew,rwhogg/brew,aw1621107/brew,mgrimes/brew,DomT4/brew,zmwangx/brew,amar-laksh/brew_sudo,bfontaine/brew,reitermarkus/brew,mgrimes/brew,muellermartin/dist,MikeMcQuaid/brew,jmsundar/brew,vitorgalvao/brew,bfontaine/brew,tonyg/homebrew,muellermartin/dist,gordonmcshane/homebrew,palxex/brew,AnastasiaSulyagina/brew,konqui/brew,EricFromCanada/brew,Homebrew/brew,mahori/brew,palxex/brew,claui/brew,reitermarkus/brew,toonetown/homebrew,AnastasiaSulyagina/brew,JCount/brew,MikeMcQuaid/brew,ilovezfs/brew,Linuxbrew/brew,Homebrew/brew,rwhogg/brew,EricFromCanada/brew,nandub/brew,gregory-nisbet/brew,tonyg/homebrew,claui/brew,maxim-belkin/brew,sjackman/homebrew,AnastasiaSulyagina/brew,nandub/brew,jmsundar/brew