Enhancement request - update to ace editor

Any chance we can update the editor to use the ACE editor https://ace.c9.io/
ACE is a powerful editor and gets most of the features that you get in brackets or atom like code folding and error highlighting.

Start by locating the current browser editor entry point and reviewing the ACE editor documentation at https://ace.c9.io/. The work is done when the editor uses ACE and provides the requested code folding and error highlighting features; the issue does not name a file or test to run.

Written by the indexing model from the issue text.