ignored line numbers in the baseline

[AlessandroMinoccheri]

Fix --ignore-baseline-linenumbers not applied when generating baseline
Fixes #620

When using --generate-baseline --ignore-baseline-linenumbers, line numbers were still written to the baseline file.

The flag only affected runtime comparison, not serialization, causing constant merge conflicts in large teams on legacy codebases.
Line numbers are now stripped before saving when --ignore-baseline-linenumbers is passed. No existing behaviour is affected — the fix only applies when both flags are used together.

[codecov]

Codecov Report

❌ Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 98.25%. Comparing base (30ad0cc) to head (7c17ca3).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/CLI/Baseline.php	66.66%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #621      +/-   ##
============================================
- Coverage     98.29%   98.25%   -0.05%     
- Complexity      696      700       +4     
============================================
  Files            87       87              
  Lines          1991     2000       +9     
============================================
+ Hits           1957     1965       +8     
- Misses           34       35       +1     

Files with missing lines	Coverage Δ
src/CLI/Command/Check.php	100.00% <100.00%> (ø)
src/Rules/Violation.php	100.00% <100.00%> (ø)
src/Rules/Violations.php	100.00% <100.00%> (ø)
src/CLI/Baseline.php	93.33% <66.66%> (-3.10%)	⬇️

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[micheleorselli]

If I got the code right, with this change if a user generates a baseline with --ignore-baseline-linenumbers then every comparison with that baseline would (obviously) ignore line numbers, meaning that if the tool is run with --ignore-baseline-linenumbers or not, it would produce the same result

⚠️ Maybe we should document this behaviour and/or make explicit if the comparison is considering line numbers or not

💭 In my opinion the long term solution should be rethinking the way the baseline works. The user should not be forced to know about line numbers, it should just work. Psalm and PHPStan do use baseline, so we could see how they do it

[AlessandroMinoccheri]

I agree @micheleorselli , I would suggest to merge this PR and create a new issue as an IDEA with your vision.
Is it ok for you?
@fain182 what do you think?

[fain182]

I think we should add a section in the readme in which document all the configurations...
ignore baseline numbers it seems more like a configuration than an option, because is something persistent.