Update argtypes.md
Update argtypes.md

As a user I miss to read that it is possible to override argTypes in a single story
storybooks/react-storybook,storybooks/react-storybook,storybooks/storybook,storybooks/storybook,storybooks/storybook,storybooks/react-storybook,storybooks/storybook,kadirahq/react-storybook,storybooks/storybook,storybooks/storybook,kadirahq/react-storybook,storybooks/storybook,storybooks/react-storybook