src/vs/editor/common/config/editorOptions.ts/EditorClassName/compute
class EditorClassName:	public compute(env: IEnvironmentalOptions, options: IComputedEditorOptions, _: string): string {
		const classNames = ['monaco-editor'];
		if (options.get(EditorOption.extraEditorClassName)) {
			classNames.push(options.get(EditorOption.extraEditorClassName));
		}
		if (env.extraEditorClassName) {
			classNames.push(env.extraEditorClassName);
		}
		if (options.get(EditorOption.mouseStyle) === 'default') {
			classNames.push('mouse-default');
		} else if (options.get(EditorOption.mouseStyle) === 'copy') {
			classNames.push('mouse-copy');
		}

		if (options.get(EditorOption.showUnused)) {
			classNames.push('showUnused');
		}

		if (options.get(EditorOption.showDeprecated)) {
			classNames.push('showDeprecated');
		}

		return classNames.join(' ');
	}