Rust port now supports compression, should maybe be listed as a full port not just as decoder

[KillingSpark]

Describe the bug
facebook.github.io/zstd/ lists the rust port as a decoder. This is outdated as of recently, there is now a published, working, encoder implementation.

To Reproduce

1. Go to website
2. look at table
3. See "Rust (decoder, Port)" listed for https://github.com/KillingSpark/zstd-rs

Expected behavior

1. Go to website
2. look at table
3. See "Rust (Port)" listed for https://github.com/KillingSpark/zstd-rs

Additional context
I'm not sure what the exact criteria are to be listed as a full port. The current encoder implementation offers no real flexibility over the compression level yet. It is able to process any data thrown at it and output valid zstd frames, compressing enwik9 to ~48% of the original size.

[Cyan4973]

Rust port listing updated

[KillingSpark]

Thanks!