feat: infer associate functions

[baszalmstra]

Adds the ability to infer the type of associate function calls.

[codecov]

Codecov Report

Attention: Patch coverage is 94.31818% with 5 lines in your changes missing coverage. Please review.

Project coverage is 87.45%. Comparing base (7c7a3c7) to head (de82798).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/mun_hir/src/ty/infer.rs	89.58%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #575      +/-   ##
==========================================
+ Coverage   87.40%   87.45%   +0.05%     
==========================================
  Files         276      276              
  Lines       32531    32609      +78     
==========================================
+ Hits        28433    28519      +86     
+ Misses       4098     4090       -8     

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