Update dependencies including proc-macro-crate

Closes #125

See merge request !506

Now, this is unblocked.

Fixes #125 by bringing in the fix to
  https://github.com/bkchr/proc-macro-crate/issues/57

LICENCE: Correct the copyright, and release

See merge request !505

Some of this has been done on work time by TPI staff.

Remove the implication that the 2022 is the copyright year.

Prepare for release  of 1.0.0

Closes #124

See merge request !504

Docs updates arising from a last-minute review

See merge request !503

This is in the TOC, but the prose should mention it or it's
incomplete.

What we're looking at probably isn't "documentation", it's just an
intro spiel and simple example.  Let's say "{+ full +} documentation",
and linkify it.

Even $(...) and $$ are allowed.

The unclosed brace confused my eye.

Since we're recommending it.

Explicitly mention the attribute that enables this, and the
derive_deftly_adhoc call.  The "exporting" can now be a subsection.
Introduce a heading for the semver hazards.

This is the less-usual case.  It can go at the end.

Update to latest stable clippy (and fix an erroneous doc comment)

See merge request !502

Spotted by clippy 1.84.

HACKING.md: Updates arising from today's nightly update

See merge request !501

Update to +nightly-2025-02-10 and cargo-expand 1.0.100

See merge request !500

The gerund makes it sound like these are things you might like to do,
rather than parts of the overall task.