Exit 0 when compiler errors exist

[dfed]

Resolves #188 by not throwing an error when compiler errors are detected. We want to exit 0 such that users' compilers can highlight the syntax error that breaks our parsing rather than encountering an issue where SafeDI incorrectly tells the user that a type does not exist that does exist.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.90%. Comparing base (845616e) to head (0a14c9c).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #189   +/-   ##
=======================================
  Coverage   99.90%   99.90%           
=======================================
  Files          32       32           
  Lines        3231     3257   +26     
=======================================
+ Hits         3228     3254   +26     
  Misses          3        3           

Files with missing lines	Coverage Δ
Sources/SafeDICore/Visitors/FileVisitor.swift	100.00% <100.00%> (ø)
Sources/SafeDITool/SafeDITool.swift	99.55% <100.00%> (+0.04%)	⬆️

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