Function convert_key 

pub fn convert_key(t: &mut Table, name: &str, to: Kind) -> bool

Change a key’s value to another kind, where it reads as one, keeping its place and its decor.

A value becomes another value through convert. A table becomes an inline table and an inline table becomes a table through toml_edit’s own conversions, which is the one change here that is about layout rather than type: [owner] and owner = { ... } hold the same thing, and which one a file uses is a decision this makes explicit. Refuses what would be a guess, and an array of tables, which is neither one table nor a value.