Add ProjectInfo.WithId

[tmat]

Background and Motivation

Useful for dotnet-watch, where we need to take ProjectInfo returned MSBuildProjectLoader and remap its ID to a project with the same project file path.

Proposed API

namespace Microsoft.CodeAnalysis;

public sealed class ProjectInfo
{
+    public ProjectInfo WithId(ProjectId id);
}

Similar API is already available for DocumentInfo.

Usage Examples

var mappedInfo = projectInfo.WithId(oldProjectId);

Alternative Designs

Risks

[333fred]

API Review

• Should we add Solution.WithId for consistency?
  • No use cases

Approved

[tmat]

Implemented by #74664