In Preferences / Themes you can add a new theme with a name that has
multiple words and the resulting file name will have spaces converted
to underscores. Unfortunately such multi-word themes will not pass the
poll function for saving and deletion. This PR just adds calls that
convert from the display name to file name in order for these to work.
Pull Request: https://projects.blender.org/blender/blender/pulls/122848
d08cebf6d7