docs: update addon-gallary
docs: update addon-gallary

fixes a minor grammatical error
storybooks/storybook,rhalff/storybook,kadirahq/react-storybook,storybooks/storybook,rhalff/storybook,kadirahq/react-storybook,storybooks/react-storybook,storybooks/storybook,storybooks/storybook,storybooks/storybook,storybooks/storybook,rhalff/storybook,storybooks/react-storybook,storybooks/storybook,rhalff/storybook,storybooks/react-storybook,storybooks/react-storybook,rhalff/storybook,rhalff/storybook