/**
 * 合并 import 语句
 * @example
 * mergeImport(`import { a } from 'a'; import { b } from 'a'; import { c } from 'a';`) //  `import { a, b, c } from 'a'`
 * @param str
 * @returns
 */
export declare function mergeImport(str: string): string;