src/vs/workbench/browser/editor.ts/EditorRegistry/registerEditor
class EditorRegistry:	registerEditor(descriptor: EditorDescriptor, inputDescriptors: readonly SyncDescriptor<EditorInput>[]): IDisposable {
		this.mapEditorToInputs.set(descriptor, inputDescriptors);

		const remove = insert(this.editors, descriptor);

		return toDisposable(() => {
			this.mapEditorToInputs.delete(descriptor);
			remove();
		});
	}