Document trailing and int encoding compared to Config on Options

[junderw]

When switching from config() to options(), it seems that fixed int behavior switched to default to varint behavior.

The trailing and int encoding options were not present in Config, so Options documentation should mention how to configure Options in the same way as the default Config.

I understand you have moved away from Options in the newest versions... but as someone using v1 latest, trying to fix the deprecation warning caused this gotcha.

[VictorKoenders]

We've written a small migration guide here: https://docs.rs/bincode/2.0.0-rc.2/bincode/migration_guide/index.html

Is this missing anything?

[junderw]

I wasn't referring to the v1 to v2 migration.

I was talking about migrating from Config to Options within the same v1.3.3 to get rid of the deprecation warnings.

I had to go digging in the source code to find the macro that implements the Config to Option conversion and see the default settings (in terms of Option) for Config.

Similar to how the config module explains the difference between Option struct and the *serialize functions and what their defaults are.

It would have been nice if the Config documentation had something similar comparing Config and Option structs in terms of the new Option's settings.

(ie. I could learn "Config was using fixint internally but you couldn't set it. So if I want the same behavior i should use fixint, which is default. cool.")