Clarify `Style Switching with Variations` description

On the 6.0 testing post, Style Switching with Variations says:

…enabling site owners to easily switch between a theme’s default or custom designed styles.

And

Variations can also be pre-configured by theme authors in theme.json.

When I read this, both of these sentences seemed to imply that I could create a custom style in the editor and switch back and forth between that and a default style. However, unless I am missing something, this doesn’t appear to be the case. If I create a custom style, I can’t switch away and switch back to it since there is no option to save that style. Discussed here. I’d suggest removing the default or custom designed part to just say enabling site owners to easily switch between a theme's style variations.

Also, to my knowledge, the only way to pre-configure a variation is through the theme.json, so I would remove the word also in the second quote.

I know that this testing guide is a bit dated now and may not need to be edited:). But for future ones and certainly the release notes, I’d describe on the main feature being enabling themes to ship multiple style variations and for users to switch between them in order to avoid this confusion for others.

The page I need help with: [log in to see the link]