Fix: preserve Python variable name for returned input aliases

[Aniketsy]

#2714

[justinchuby]

@Aniketsy thanks, could you resolve the merge conflicts?

[Aniketsy]

Sorry, I'll fix this

[Aniketsy]

@justinchuby please review these, when you get a chance, I've fixed conflicts.

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 70.45%. Comparing base (a9cb429) to head (90b45cc).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
onnxscript/_internal/converter.py	80.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2788      +/-   ##
==========================================
- Coverage   70.45%   70.45%   -0.01%     
==========================================
  Files         228      228              
  Lines       27177    27180       +3     
  Branches     2734     2735       +1     
==========================================
+ Hits        19148    19150       +2     
  Misses       7092     7092              
- Partials      937      938       +1     

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