Bincode 2 updated documentation

[VictorKoenders]

Some things that I need to document

• Document implementing Decode and Encode manually Update documentation #480
• List of config options to use for max compression/performance/etc Update documentation #480
• See Config for more information on the configuration options. needs to point to Configuration Update documentation #480
• Best practice of adding const CONFIG: Configuration = Configuration::standard().with_xxx(); to your binary
• Make docs consistent about fixed-size array length encoding Update documentation #480
• Fix Decoder::config() incorrectly reporting it returns a mutable reference Update documentation #480
• Migration guide Migration guide #482

[jrose-signal]

The docs are also currently inconsistent about whether a fixed-size array is encoded with its length or not. I see that that's a configuration option now, so probably both places that mention it need to be updated!

[5225225]

https://docs.rs/bincode/2.0.0-beta.0/bincode/de/trait.Decoder.html#tymethod.config

The doc wording here talks about a mutable reference but it gives a &Self::C

[rapiz1]

What about the migration guide? I'm curious about bincode v2's departure from serde and don't know if I should upgrade. It will be helpful to see documentation and the motivation of bincode v2.

[VictorKoenders]

What about the migration guide?

Migrating with serde should be simple, enable the serde feature and use the functions in bincode::serde.

A bigger write-up in #482