fix popups being covered by page scrollbar

[nightwing]

Fixes the issue where autocomplete popup and doc tooltip could be covered by page scrollbar, or could extend outside of viewport.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.15%. Comparing base (cd78a94) to head (f142dbf).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5763      +/-   ##
==========================================
+ Coverage   87.10%   87.15%   +0.04%     
==========================================
  Files         602      602              
  Lines       44092    44157      +65     
  Branches     7234     7240       +6     
==========================================
+ Hits        38407    38484      +77     
+ Misses       5685     5673      -12     

Flag	Coverage Δ
unittests	87.15% <100.00%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ 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.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.