Fixes#46
When comparing two different `KdlNode` or `KdlDocument`, it's useful to
have a "canonical" representation where formatting differences do not
matter.
`clear_fmt` removes all formatting from a `KdlNode`, but does not apply
recursively, as a result, it doesn't create a canonical representation.
`clear_fmt_recursive` solves this by applying `clear_fmt` recursively to
the contents of the node.
This commit includes a whole bunch of fixes, some of which are significant changes to the parser and some related functionality. But I consider all changes to be bugfixes because they were compliance failures.
This new version of kdl-rs is a complete rewrite that introduces
a formatting-aware-and-preserving parser, much like toml_edit et al.
BREAKING CHANGE: Completely new API and bumped MSRV to 1.56.0.
Christopher Durham
Nicola Papale
Kat Marchán