docs(addons): add hint about addon tab order
docs(addons): add hint about addon tab order

which I missed and I guess would be rather helpful
for others searching for this.

fixes #6019

storybooks/storybook,storybooks/react-storybook,storybooks/storybook,storybooks/storybook,kadirahq/react-storybook,storybooks/storybook,kadirahq/react-storybook,storybooks/storybook,storybooks/react-storybook,storybooks/storybook,storybooks/react-storybook,storybooks/react-storybook,storybooks/storybook