Rename Joy UI CSS variables

Proprietary

Renames the CSS variables of Joy UI components in string literals to the new naming standard, and --internal- and --private_ to --unstable_.

org.openrewrite.react.mui.rename-joy-css-variables
mod run . --recipe=org.openrewrite.react.mui.rename-joy-css-variables

Install it once, then run it on every repository under the current directory. New to the Moderne CLI? Set it up.