[simontreanor]

Bumps the four versioned artifacts (Cargo.toml/Cargo.lock, the VS Code extension, the JetBrains plugin, the Emacs mode) to 0.10.0, with a VS Code changelog entry. No client code changes.

Minor rather than patch: an Async value is now cold (#177), so Python code that ran a Pyfun async value with asyncio.run(job) calls it, asyncio.run(job()).

Checked on this branch before the tag:

• cargo fmt, cargo clippy --all-targets (clean), cargo test (every binary), the lessons and notebooks, and tests/kernel_e2e.py all pass.
• tests/native_parity.py: 84 of 84.
• A wheel built from this branch with maturin 1.15.0, installed in a fresh venv, passes 16 checks of the release's headline features: cold re-runs, an asyncio.start_server callback, a partially applied async extern, Python calling a Pyfun Async, each new hint, the closed-callback hint, and native builds that match plain runs.
• Every e2e program under Python 3.12 in Docker matches Windows/3.14 except glibc's math.cbrt(27.0) (286 of 287). That run found lexer: a line break in a string is \n whatever the file's line endings #182, fixed and merged before this bump.

The tag goes on the merged commit afterwards, per RELEASING.md.