[mode/meta] Add "jl" alias for Julia
[mode/meta] Add "jl" alias for Julia

Closes #6642
wingify/CodeMirror,nightwing/CodeMirror,hackmdio/CodeMirror,pabloferz/CodeMirror,hackmdio/CodeMirror,wingify/CodeMirror,wingify/CodeMirror,dperetti/CodeMirror,nightwing/CodeMirror,pabloferz/CodeMirror,pabloferz/CodeMirror,hackmdio/CodeMirror,nightwing/CodeMirror,dperetti/CodeMirror,dperetti/CodeMirror