formula.rb: define `elisp` and `opt_elisp`
formula.rb: define `elisp` and `opt_elisp`

Closes Homebrew/homebrew#45567.

Signed-off-by: Alex Dunn <46952c1342d5ce1a4f5689855eda3c9064bca8f6@gmail.com>

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