Use default light code theme

Author: benjeffery

docs/_config.yml

@@ -44,7 +44,6 @@ sphinx:
     config:
       html_theme: sphinx_book_theme
       html_theme_options:
-        pygment_light_style: monokai
         pygment_dark_style: monokai
       pygments_style: monokai
       myst_enable_extensions: