seq: eliminate special handling of -0.0

[jfinkels]

The seq program contains a lot of code for representing and displaying floating point negative zero (-0.0f32, for example). It should be possible to eliminate some of this code once the minimum supported version of Rust reaches v1.52.0 or greater. See the comments in pull request #2698 for more information.

Pull request #2869 proposes increasing the minimum version to v1.54.0, so that would allow this change.

See rust-lang/rust#78618 for information on the relevant feature of Rust.

[tertsdiepraam]

The MSRV is now 1.54, so this is unblocked.

[palaster]

This can be closed because of this #3056