Add lunr extension for doc search

[mborland]

No description provided.

[cppalliance-bot]

An automated preview of the documentation is available at https://294.int128.prtest3.cppalliance.org/libs/int128/doc/html/index.html

If more commits are pushed to the pull request, the docs will rebuild at the same URL.

2026-01-16 20:24:38 UTC

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.57%. Comparing base (b05fdc2) to head (e99c269).
⚠️ Report is 4 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #294   +/-   ##
========================================
  Coverage    99.57%   99.57%           
========================================
  Files           54       54           
  Lines         4929     4929           
  Branches      1429     1429           
========================================
  Hits          4908     4908           
  Misses          21       21           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.