Add some styling for Releases changelog pages.
Add some styling for Releases changelog pages.

ellisonbg/jupyter-alabaster-theme,bgeron/alabaster,nikolas/alabaster,ellisonbg/jupyter-alabaster-theme,charnpreetsingh/jupyter-alabaster-theme,bgeron/alabaster,jupytercalpoly/jupyter-alabaster-theme,ellisonbg/jupyter-alabaster-theme,jupytercalpoly/jupyter-alabaster-theme,charnpreetsingh/jupyter-alabaster-theme,nikolas/alabaster,jupytercalpoly/jupyter-alabaster-theme,charnpreetsingh/jupyter-alabaster-theme