C#: Remove unused classes from Util project

Author: tamasvajk

csharp/autobuilder/Semmle.Autobuild.CSharp/DotNetRule.cs

@@ -32,7 +32,7 @@ public BuildScript Analyse(IAutobuilder<CSharpAutobuildOptions> builder, bool au
             if (auto)
             {
                 NotDotNetProjects = builder.ProjectsOrSolutionsToBuild
-                    .SelectMany(p => Enumerators.Singleton(p).Concat(p.IncludedProjects))
+                    .SelectMany(p => new[] { p }.Concat(p.IncludedProjects))
                     .OfType<Project<CSharpAutobuildOptions>>()
                     .Where(p => !p.DotNetProject);
                 var notDotNetProject = NotDotNetProjects.FirstOrDefault();

csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Lambda.cs

@@ -63,7 +63,7 @@ private Lambda(ExpressionNodeInfo info, ParenthesizedLambdaExpressionSyntax node
         public static Lambda Create(ExpressionNodeInfo info, ParenthesizedLambdaExpressionSyntax node) => new Lambda(info, node);
 
         private Lambda(ExpressionNodeInfo info, SimpleLambdaExpressionSyntax node)
-            : this(info.SetKind(ExprKind.LAMBDA), node.Body, Enumerators.Singleton(node.Parameter), null) { }
+            : this(info.SetKind(ExprKind.LAMBDA), node.Body, [node.Parameter], null) { }
 
         public static Lambda Create(ExpressionNodeInfo info, SimpleLambdaExpressionSyntax node) => new Lambda(info, node);