Refactor of AlgTerm/AlgType to use good sumtypes

[olynch]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 90.75026% with 90 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.56%. Comparing base (bd3df8e) to head (1668f3b).
⚠️ Report is 29 commits behind head on main.

Files with missing lines	Patch %	Lines
src/syntax/gats/ast.jl	84.56%	23 Missing ⚠️
src/syntax/gats/algorithms.jl	77.90%	19 Missing ⚠️
src/util/Dtrys.jl	95.15%	11 Missing ⚠️
src/nonstdlib/dynamics/ResourceSharers.jl	94.79%	9 Missing ⚠️
src/util/MyActive.jl	81.81%	6 Missing ⚠️
src/models/ModelInterface.jl	86.48%	5 Missing ⚠️
src/util/SumTypes.jl	94.62%	5 Missing ⚠️
src/syntax/gats/exprinterop.jl	93.84%	4 Missing ⚠️
src/syntax/gats/closures.jl	95.23%	3 Missing ⚠️
src/syntax/gats/gat.jl	70.00%	3 Missing ⚠️
... and 2 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #158      +/-   ##
==========================================
- Coverage   93.85%   84.56%   -9.30%     
==========================================
  Files          38       41       +3     
  Lines        2229     2837     +608     
==========================================
+ Hits         2092     2399     +307     
- Misses        137      438     +301     

☔ View full report in Codecov by Harness.
📢 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.