Fix a typo that shows up in the UI.
Fix a typo that shows up in the UI.

jupyter/jupyter-js-plugins,blink1073/jupyter-js-plugins,blink1073/jupyter-js-plugins,blink1073/jupyter-js-plugins,jupyter/jupyter-js-plugins,jupyter/jupyter-js-plugins,jupyter/jupyter-js-plugins,jupyter/jupyter-js-plugins,blink1073/jupyter-js-plugins,blink1073/jupyter-js-plugins