feat(patch): Allow to use swift-syntax 603

[freef4ll]

Description

Include a summary of the change and which issue is fixed. Please also include relevant motivation and context.

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Minimal checklist:

• I have performed a self-review of my own code
• I have added DocC code-level documentation for any public interfaces exported by the package
• I have added unit and/or integration tests that prove my fix is effective or that my feature works

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.76%. Comparing base (c0f1c48) to head (d320d29).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #37      +/-   ##
==========================================
- Coverage   92.80%   90.76%   -2.04%     
==========================================
  Files          16       16              
  Lines         500      357     -143     
==========================================
- Hits          464      324     -140     
+ Misses         36       33       -3     

see 15 files with indirect coverage changes
see 15 files with indirect coverage changes

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[gemini-code-assist]

Code Review

This pull request updates the swift-syntax dependency to version 603.0.1 and expands the supported version range in Package.swift. A review comment identifies a compatibility risk, noting that swift-syntax versions are strictly coupled with specific Swift compiler versions; using a newer version without updating the swift-tools-version may cause build failures for users on older toolchains.