process: mark process.finalization as release candidate

[mcollina]

Moves process.finalization.register(), registerBeforeExit() and unregister() from Stability 1.1 (Active Development) to 1.2 (Release candidate) and drops the experimental warning.

---

AI generated, reviewed by me

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.38%. Comparing base (ebef774) to head (5ead480).
⚠️ Report is 286 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66436      +/-   ##
==========================================
+ Coverage   90.28%   90.38%   +0.10%     
==========================================
  Files         790      792       +2     
  Lines      271642   275719    +4077     
  Branches    51846    52864    +1018     
==========================================
+ Hits       245260   249220    +3960     
- Misses      16889    16896       +7     
- Partials     9493     9603     +110     

Files with missing lines	Coverage Δ
lib/internal/process/finalization.js	100.00% <ø> (ø)

... and 195 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.