src/vs/workbench/contrib/files/browser/editors/textFileEditor.ts/TextFileEditor/openAsFolder
class TextFileEditor:	private async openAsFolder(input: FileEditorInput): Promise<void> {
		if (!this.group) {
			return;
		}

		// Since we cannot open a folder, we have to restore the previous input if any and close the editor
		await this.group.closeEditor(this.input);

		// Best we can do is to reveal the folder in the explorer
		if (this.contextService.isInsideWorkspace(input.preferredResource)) {
			await this.viewletService.openViewlet(VIEWLET_ID);

			this.explorerService.select(input.preferredResource, true);
		}
	}