[mode/simple addon] Allow token source to be a function
[mode/simple addon] Allow token source to be a function

Issue #4787

notepadqq/CodeMirror,ficristo/CodeMirror,jayaprabhakar/CodeMirror,thomasjm/CodeMirror,codio/CodeMirror,jkaplon/CodeMirror,mtaran-google/CodeMirror,SidPresse/CodeMirror,notepadqq/CodeMirror,ficristo/CodeMirror,wingify/CodeMirror,namin/CodeMirror,hackmdio/CodeMirror,namin/CodeMirror,pabloferz/CodeMirror,dperetti/CodeMirror,wingify/CodeMirror,MarcelGerber/CodeMirror,MarcelGerber/CodeMirror,nightwing/CodeMirror,dperetti/CodeMirror,nightwing/CodeMirror,codio/CodeMirror,mtaran-google/CodeMirror,thomasjm/CodeMirror,jayaprabhakar/CodeMirror,mtaran-google/CodeMirror,jkaplon/CodeMirror,thomasjm/CodeMirror,SidPresse/CodeMirror,nightwing/CodeMirror,pabloferz/CodeMirror,MarcelGerber/CodeMirror,ficristo/CodeMirror,SidPresse/CodeMirror,dperetti/CodeMirror,notepadqq/CodeMirror,wingify/CodeMirror,namin/CodeMirror,hackmdio/CodeMirror,jkaplon/CodeMirror,codio/CodeMirror,hackmdio/CodeMirror,pabloferz/CodeMirror,jayaprabhakar/CodeMirror