pub fn rename_file(root: &Path) -> Result<PathBuf, String>Expand description
Renames the file’s first name, sioul-cases.toml, to
sioul-projects.toml, and its [[case]] tables to [[project]], in one
write: every field, route and comment kept, and checked to be so before
anything is written. The old file stays beside the new one, as
sioul-cases.toml.before-rename. Never done by itself: an older Sioul
reads only the first name, so the person chooses when (Settings ▸ Your
folder and sharing). Refused when sioul-projects.toml is already there.
Returns where the old file was kept.