(mostly) Support extended diagnostic notation

[Nemo157]

Mostly implements support for extended diagnostic notation from RFC 8610 https://datatracker.ietf.org/doc/html/rfc8610#appendix-G

Only missing support for comments, supporting those inside bytestrings will be painful.

Also fixes #108, both the whitespace from EDN and the other issues identified (lack of padding).

[Nemo157]

bors r+

[bors[bot]]

Build succeeded:

• cargo build --target wasm32-unknown-unknown
• cargo build -z minimal-versions
• cargo clippy
• cargo fmt --check
• cargo test
• cargo test (stable, i686-pc-windows-msvc, windows-latest)
• cargo test (stable, i686-unknown-linux-gnu, ubuntu-latest)
• cargo test (stable, x86_64-apple-darwin, macos-latest)
• cargo test (stable, x86_64-pc-windows-msvc, windows-latest)
• cargo test (stable, x86_64-unknown-linux-gnu, ubuntu-latest)