Comma outside of array or object is not necessarily trailing
Comma outside of array or object is not necessarily trailing

This code catches things like `[1, 2], 3` where the `, 3` are trailing
characters but the comma is not a trailing comma. Trailing comma is like
the commas in `[1,]` or `{"f":2,}`.

google/serde_json_lenient,bolinfest/serde-jsonrc,serde-rs/json