feat: add user implemented void mapping methods

[TimothyMakkison]

Let mapperly use user implemented existing target methods

Description

Add user implemented existing target mapping methods. Mapperly will attempt to use the users methods where possible

I can add support for reusing user defined void mappings, it should be a different PR.

Fixes #439

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)

[codecov]

Codecov Report

Merging #569 (67f3016) into main (3d2ed69) will decrease coverage by 0.07%.
Report is 1 commits behind head on main.
The diff coverage is 86.20%.

❗ Current head 67f3016 differs from pull request most recent head 7efb65d. Consider uploading reports for the commit 7efb65d to get more accurate results

@@            Coverage Diff             @@
##             main     #569      +/-   ##
==========================================
- Coverage   90.53%   90.46%   -0.07%     
==========================================
  Files         173      175       +2     
  Lines        5956     6032      +76     
  Branches      756      762       +6     
==========================================
+ Hits         5392     5457      +65     
- Misses        398      404       +6     
- Partials      166      171       +5     

Files Changed	Coverage Δ
...scriptors/InlineExpressionMappingBuilderContext.cs	95.91% <ø> (ø)
...Riok.Mapperly/Descriptors/MappingBuilderContext.cs	100.00% <ø> (ø)
...iptors/MappingBuilders/DictionaryMappingBuilder.cs	90.82% <ø> (ø)
.../MappingBuilders/DirectAssignmentMappingBuilder.cs	100.00% <ø> (ø)
.../Descriptors/MappingBuilders/EnumMappingBuilder.cs	84.75% <ø> (ø)
...tors/MappingBuilders/EnumToStringMappingBuilder.cs	100.00% <ø> (ø)
...iptors/MappingBuilders/EnumerableMappingBuilder.cs	94.83% <ø> (ø)
...escriptors/MappingBuilders/MemoryMappingBuilder.cs	88.46% <ø> (ø)
...uilders/NewInstanceObjectPropertyMappingBuilder.cs	91.17% <ø> (ø)
...criptors/MappingBuilders/NullableMappingBuilder.cs	92.85% <ø> (ø)
... and 46 more

... and 2 files with indirect coverage changes

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[TimothyMakkison]

Should I update the docs under user implemented mappings or void mappings?

[latonz]

@TimothyMakkison I'll review the open PR's after 2.9.0 is released (we plan to release it next week). You can probably wait until the code / API changes are reviewed. If sth. fundamental changes after the review on the API surface, you then don't need to rewrite the docs again.

[TimothyMakkison]

• Made suggested chnages
• Reworked ITypeMapping

Would it be worth making AddExisting and AddNewInstance private and using MappingCollection.Add directly? Should I create issues for reuse existing target user defined and reuse existing target mapping methods?
I haven't updated the docs.

[latonz]

@TimothyMakkison feel free to create the issues.
I'd keep AddExisting and AddNewInstance public and call them if the type is known. This has a little performance benefit since the runtime type switch is not needed.

[latonz]

2 Nitpicks and rebasing, afterwards this can get merged 😊

[TimothyMakkison]

2 Nitpicks and rebasing, afterwards this can get merged 😊

Thanks for the review, done the changes. 👍

I think it will be best to update the docs after all the other void mappings are completed

[github-actions]

🎉 This PR is included in version 3.1.0-next.1 🎉

The release is available on:

• GitHub release
• v3.1.0-next.1

Your semantic-release bot 📦🚀

[github-actions]

🎉 This PR is included in version 3.1.0 🎉

The release is available on:

• GitHub release
• v3.1.0

Your semantic-release bot 📦🚀