* Update Copybara options in preparation for open-sourcing the source editor
* Move files
* Update paths
* Remove source-editor module and checks for its existence
* Explicitly mention CM6 license in files that contain code adapted from CM6
GitOrigin-RevId: 89b7cc2b409db01ad103198ccbd1b126ab56349b
* Add a source editor toggle
* Only show the toggle if in split test variant (or query param override)
* Change labels
* Add check for this.editor
* Update toolbar.pug
GitOrigin-RevId: ee00e31db334fc562b00d28a8c2de5d03456f749