More accurate filename in case of error when parsing component
More accurate filename in case of error when parsing component

This avoid "Error when parsing index.js" and offer a better filename like "Error when parsing web_modules/SidebarItem/index.js".
styleguidist/react-styleguidist,styleguidist/react-styleguidist,bluetidepro/react-styleguidist,styleguidist/react-styleguidist,sapegin/react-styleguidist,sapegin/react-styleguidist