v7: No option selectable in Editor Syntax highlighting.

[Carreau]

I'm not sure if it's a bug or not, either something is wrong or the menu should be removed ?

[RRosio]

Thank you @Carreau! Per the triage meeting, some of the languages listed here are really unusual and maybe not commonly used. It is maybe safe to remove this option and only add it if people really need it.

[JasonWeill]

As observed at the JupyterLab meeting, this should only be operable in text files, not in notebooks' code cells.

This menu item should be hidden entirely when the user is using a notebook.