docs: Remove note about musl binary distributions

[Wingysam]

Summary

Now that uv installs Python in musl-based environments (#12121), the docs no longer need to call out that it cannot do this.

Test Plan

Docs-only change.

Question

Should this documentation still call out that it can't install Python on arm systems?

[zanieb]

Thank you! Should we amend this to note that this is the case for aarch64 images instead of deleting it?

[zanieb]

ha, I see you asked this — I'd be more comfortable mentioning aarch64 / arm64 until we ship support there.