feat: generate diagnostic warning when ignored members are explicitly mapped

[mikeguta]

Add a diagnostic if an explicitly ignored member is mapped explicitly

Description

Ignored members could also be explicitly mapped, but this may not be intended. This change adds warning level diagnostic messages when either a source or a target member is in that situation, but should not alter the behaviour of the library.

Fixes #512 (using the approach specified in its description)

Checklist

• The existing code style is followed
• The commit message follows our guidelines
• Performed a self-review of my code
• Hard-to-understand areas of my code are commented
• The documentation is updated (as applicable)
• Unit tests are added/updated
• Integration tests are added/updated (as applicable, especially if feature/bug depends on roslyn or framework version in use)

[latonz]

Thank you for your first contribution to Mapperly 😊
I added some feedback, feel free to discuss the feedback provided or ask questions if sth. is not clear.

Since this is your first contribution I need to manually approve the CI run each time you contribute, I'll try to do this as fast as I can so that fast feedback is provided to you. However, if it is still too slow, you can create a PR against your own fork.

[codecov]

Codecov Report

Merging #708 (de29460) into main (a63035b) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #708      +/-   ##
==========================================
+ Coverage   91.15%   91.21%   +0.05%     
==========================================
  Files         198      198              
  Lines        6557     6601      +44     
  Branches      816      820       +4     
==========================================
+ Hits         5977     6021      +44     
  Misses        389      389              
  Partials      191      191              

Files Changed	Coverage Δ
...ers/BuilderContext/MembersMappingBuilderContext.cs	100.00% <100.00%> (ø)
...Riok.Mapperly/Diagnostics/DiagnosticDescriptors.cs	100.00% <100.00%> (ø)

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[latonz]

Thank you for the updates, lgtm 😊

[github-actions]

🎉 This PR is included in version 3.2.0-next.2 🎉

The release is available on:

• GitHub release
• v3.2.0-next.2

Your semantic-release bot 📦🚀

[github-actions]

🎉 This PR is included in version 3.2.0 🎉

The release is available on:

• GitHub release
• v3.2.0

Your semantic-release bot 📦🚀