src/vs/workbench/common/editor/sideBySideEditorInput.ts/SideBySideEditorInput/save
class SideBySideEditorInput:	override async save(group: GroupIdentifier, options?: ISaveOptions): Promise<EditorInput | IUntypedEditorInput | undefined> {
		const primarySaveResult = await this.primary.save(group, options);

		return this.saveResultToEditor(primarySaveResult);
	}