EnableGenerateDocumentationFile analyzer is a breaking change

[jaredpar]

The diagnostic added in #58835 is an unconditional diagnostic that fires on existing code. That means it represents a breaking change to customers when upgrading to a new version of the .NET SDK toolset. This was discovered by 1P customers trying to upgrade and represents a blocker for them. This diagnostic needs to be conditioned on a warning version at the least.

[sharwell]

It seems straightforward to condition this on warning version.

Note that this is already conditioned on two separate non-default configurations being applied by the customer (explicitly enabling code style diagnostics on build, and explicitly raising the severity of IDE0005 to warning or greater).

[rainersigwald]

explicitly raising the severity of IDE0005 to warning or greater

In the internal codebase in question it appears to be configured (via .ruleset) to Info.

This was overridden back up to Warning by other configuration.

[sharwell]

EnableGenerateDocumentationFile only reports a diagnostic when IDE0005 is configured to warning or greater (the default is lower severity, and will not result in a warning).

roslyn/src/Analyzers/Core/Analyzers/RemoveUnnecessaryImports/AbstractRemoveUnnecessaryImportsDiagnosticAnalyzer.cs

Lines 121 to 125 in b801bf2

	var effectiveSeverity = _classificationIdDescriptor.GetEffectiveSeverity(compilation.Options, tree, context.Options);
	if (effectiveSeverity is ReportDiagnostic.Warn or ReportDiagnostic.Error)
	{
	context.ReportDiagnostic(Diagnostic.Create(s_enableGenerateDocumentationFileIdDescriptor, Location.None));
	}

[arunchndr]

cc: @mavasani