Incorrect handling of default values

[Dante-101]

The plugin incorrectly identifies the arguments of the function if an argument is taking a default value with a comma.

For instance, for separator: string = ',' it ends up detecting single quote ' as an argument.

/**
 * @param  {string} csvHeader
 * @param  {object[]} objs
 * @param  {string='} separator
 * @param  {} '
 * @returns string
 */
export function jsonArrToCsv(csvHeader: string, objs: object[], separator: string = ','): string