/**
 * Modifies the given content by adding a plugin to a specified path within the content.
 *
 * @param {Object} options - Options for adding a plugin.
 * @param {string} options.content - The content to modify.
 * @param {string} options.targetPath - The dot-separated path where the plugin will be added.
 * @param {string} options.pluginName - The name of the plugin to add.
 * @returns {string} The modified content with the added plugin.
 */
export declare function addPlugin({ content, targetPath, pluginName, }: {
    content: string;
    targetPath: string;
    pluginName: string;
}): string;