Mostly some small bugfixes, with a few small new features:

- Add Position.Col, to mark the column an error occurred (#410)

- Print more detailed errors in the `tomlv` CLI.

- Ensure ParseError.Message is always set (#411)

- Allow custom string types as map keys (#414)

- Mark meta keys as decoded when using Unmarshaler interface (#426)

- Fix encoding when nested inline table ends with map (#438)

- Fix encoding of several layers of embedded structs (#430)

- Fix ErrorWithPosition panic when there is no newline in the TOML document (#433)

TOML 1.1 is now enabled by default. The TOML changelog has an overview of changes: https://github.com/toml-lang/toml/blob/main/CHANGELOG.md

Also two small fixes:

- Encode large floats as exponent syntax so that round-tripping things like `5e+22` is correct.

- Using duplicate array keys would not give an error:

      arr = [1]
      arr = [2]

  This will now correctly give a "Key 'arr' has already been defined" error.