Diagnostics using source generator

[erri120]

Diagnostics can now be created using a template builder:

    [DiagnosticTemplate]
    private static readonly IDiagnosticTemplate Diagnostic1Template = DiagnosticTemplateBuilder
        .Start()
        .WithId(new DiagnosticId(source: "Example", number: 1))
        .WithSeverity(DiagnosticSeverity.Warning)
        .WithMessage("Mod '{ModA}' conflicts with '{ModB}'!", messageBuilder => messageBuilder
            .AddDataReference<ModReference>("ModA")
            .AddDataReference<ModReference>("ModB")
        )
        .Finish();

This will generate the following method and struct:

	internal static global::NexusMods.Abstractions.Diagnostics.Diagnostic<Diagnostic1MessageData> CreateDiagnostic1(global::NexusMods.Abstractions.Diagnostics.References.ModReference ModA, global::NexusMods.Abstractions.Diagnostics.References.ModReference ModB)
	{
		var messageData = new Diagnostic1MessageData(ModA, ModB);

		return new global::NexusMods.Abstractions.Diagnostics.Diagnostic<Diagnostic1MessageData>
		{
			Id = new global::NexusMods.Abstractions.Diagnostics.DiagnosticId(source: "Example",number: 1),
			Severity = global::NexusMods.Abstractions.Diagnostics.DiagnosticSeverity.Warning,
			Message = global::NexusMods.Abstractions.Diagnostics.DiagnosticMessage.From("Mod '{ModA}' conflicts with '{ModB}'!"),
			MessageData = messageData,
			DataReferences = new global::System.Collections.Generic.Dictionary<global::NexusMods.Abstractions.Diagnostics.References.DataReferenceDescription, global::NexusMods.Abstractions.Diagnostics.References.IDataReference>
			{
				{ global::NexusMods.Abstractions.Diagnostics.References.DataReferenceDescription.From("ModA"), messageData.ModA },
				{ global::NexusMods.Abstractions.Diagnostics.References.DataReferenceDescription.From("ModB"), messageData.ModB },
			},
		};
	}

	internal readonly struct Diagnostic1MessageData
	{
		public readonly global::NexusMods.Abstractions.Diagnostics.References.ModReference ModA;
		public readonly global::NexusMods.Abstractions.Diagnostics.References.ModReference ModB;

		public Diagnostic1MessageData(global::NexusMods.Abstractions.Diagnostics.References.ModReference ModA, global::NexusMods.Abstractions.Diagnostics.References.ModReference ModB)
		{
			this.ModA = ModA;
			this.ModB = ModB;
		}

	}

This generator isn't complete yet, and this PR is only to get started with some basic source generation. I'm going to create an epic to go over some future features of our diagnostic system.

[codecov-commenter]

Codecov Report

Attention: 273 lines in your changes are missing coverage. Please review.

Comparison is base (596d997) 58.18% compared to head (37b588c) 57.93%.

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #975      +/-   ##
==========================================
- Coverage   58.18%   57.93%   -0.25%     
==========================================
  Files         637      644       +7     
  Lines       20564    21058     +494     
  Branches     1572     1642      +70     
==========================================
+ Hits        11966    12201     +235     
- Misses       8240     8467     +227     
- Partials      358      390      +32     

Flag	Coverage Δ
Linux	57.26% <50.18%> (-0.15%)	⬇️
Windows	57.18% <50.18%> (-0.20%)	⬇️
clean_environment_tests	57.91% <50.18%> (-0.25%)	⬇️
macOS	56.63% <50.18%> (-0.24%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...NexusMods.Abstractions.FileExtractor/Signatures.cs	100.00% <100.00%> (ø)
...s/NexusMods.Games.BethesdaGameStudios/Constants.cs	100.00% <100.00%> (ø)
...sMods.Games.BethesdaGameStudios/PluginOrderFile.cs	66.66% <100.00%> (ø)
...udios/SkyrimSpecialEdition/SkyrimSpecialEdition.cs	69.23% <100.00%> (ø)
...ountAndBlade2Bannerlord/Emitters/BuiltInEmitter.cs	57.14% <100.00%> (ø)
...Games/NexusMods.Games.StardewValley/Diagnostics.cs	100.00% <100.00%> (ø)
...nerators.Diagnostics/CustomSymbolDisplayFormats.cs	100.00% <100.00%> (ø)
src/NexusMods.App.UI/Initializers.cs	60.00% <100.00%> (-4.71%)	⬇️
src/NexusMods.App.UI/ReactiveUIExtensions.cs	86.27% <ø> (ø)
....StandardGameLocators.TestHelpers/ListFilesTool.cs	100.00% <100.00%> (ø)
... and 14 more

... and 4 files with indirect coverage changes

[Al12rs]

This can be merged for now with the Caveat of the things we discussed in call before.

Mainly allowing the definition of custom link handlers rather than just having a limited set of operations to do.