Readline multiline completer

[Han5991]

Fixes: #60952

Reset prevRows for multiline prompts during tab completion so the refresh doesn’t wipe the completion list, and add a regression test
that simulates a multiline prompt to verify completions remain visible

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.53%. Comparing base (e28656a) to head (1709dbc).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #60981      +/-   ##
==========================================
+ Coverage   88.51%   88.53%   +0.01%     
==========================================
  Files         703      703              
  Lines      208496   208499       +3     
  Branches    40213    40219       +6     
==========================================
+ Hits       184555   184595      +40     
+ Misses      15955    15924      -31     
+ Partials     7986     7980       -6     

Files with missing lines	Coverage Δ
lib/internal/readline/interface.js	97.35% <100.00%> (+<0.01%)	⬆️

... and 45 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.