Add tree widget

src/Spectre.Console/Rendering/Segment.cs

@@ -52,6 +52,13 @@ namespace Spectre.Console.Rendering
         /// </summary>
         public static Segment Empty { get; } = new Segment(string.Empty, Style.Plain, false, false);
 
+        /// <summary>
+        /// Creates padding segment.
+        /// </summary>
+        /// <param name="size">Number of whitespace characters.</param>
+        /// <returns>Segment for specified padding size.</returns>
+        public static Segment Padding(int size) => new(new string(' ', size));
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Segment"/> class.
         /// </summary>