In order to recolor icons based on themes, some svg icons have specific
ID names. These names are currently of the pattern "blender.some_name".
However, although CSS ID names are allowed to contain a period in them,
these are problematic as selectors. This is because #tagname.something
looks like a combination of ID and class name. Although these can be
escaped like #tagname\.something that is a pain. This PR replaces the
periods with underscores.
Pull Request: https://projects.blender.org/blender/blender/pulls/126709
bc43d243bb