docs.rs: set targets

[phip1611]

Make sure we build the docs for a variety of targets. Technically, the
doc is the same for every target; this way - however - we can better
indicate that this crate is indeed compatible with every platform.

https://blog.rust-lang.org/2026/04/04/docsrs-only-default-targets/

[phil-opp]

Looks good! Nice that we can build directly for the supported none targets.

[mkroening]

The changes themselves look good to me.

I am not sure whether this would go against the intent of the change you linked:

Most crates do not compile different code for different targets, so building fewer targets by default is a better fit for most releases. It also reduces build times and saves resources on docs.rs.

As this crate only removes code on non-x86, it might be sensible to only build docs for x86_64-unknown-none and let doc_cfg do the rest, as it currently does already.

To achieve the goal of indicating that every target is supported, maybe the current docs are highlighting this enough already.

This is just my gut feeling, though. You are welcome to go ahead with this anyway if you feel differently. :)

[phip1611]

Makes sense! thanks for your input, Martin!