Improve uninitialized variable warnings

[WardBrian]

Fixes several issues:

• Functions are no longer considered uninitialized variables in things like higher-order function calls
• Uses of uninitialized variables from the transformed data block now properly lead to warnings
• Repeated uses of the same variable only warn on the first one

Submission Checklist

• Run unit tests
• Documentation
  • If a user-facing facing change was made, the documentation PR is here:
  • OR, no user-facing changes were made

Release notes

Improved the uninitialized variable warnings raised by pedantic mode and --warn-uninitialized.

Copyright and Licensing

By submitting this pull request, the copyright holder is agreeing to
license the submitted work under the BSD 3-clause license (https://opensource.org/licenses/BSD-3-Clause)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.33%. Comparing base (bcc346b) to head (6f069be).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1579      +/-   ##
==========================================
+ Coverage   90.30%   90.33%   +0.03%     
==========================================
  Files          65       65              
  Lines       10043    10049       +6     
==========================================
+ Hits         9069     9078       +9     
+ Misses        974      971       -3     

Files with missing lines	Coverage Δ
...c/analysis_and_optimization/Dependence_analysis.ml	100.00% <100.00%> (ø)
src/analysis_and_optimization/Mir_utils.ml	76.84% <100.00%> (+0.78%)	⬆️
src/analysis_and_optimization/Pedantic_analysis.ml	95.17% <100.00%> (+0.08%)	⬆️

... and 1 file 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.