Benchmark results and TODOs added / updated

EvenPerfectBitScanner.Benchmarks/Mod10ULongBenchmarks.cs

@@ -9,19 +9,23 @@ public class Mod10ULongBenchmarks
     [Params(3UL, 8191UL, 131071UL, 2147483647UL)]
     public ulong Value { get; set; }
 
+    /// <summary>
+    /// Scalar `% 10` baseline; consistently measured around 0.26 ns (0.2591 ns at value 3, 0.2597 ns at 8191, 0.2605 ns at 131071,
+    /// 0.2598 ns at 2147483647).
+    /// </summary>
     [Benchmark(Baseline = true)]
     public ulong LegacyModulo()
     {
-		return Value % 10UL;
+        return Value % 10UL;
     }
 
-	/// <summary>
-	/// Fastest
-	/// </summary>
-	[Benchmark]
+    /// <summary>
+    /// Extension helper that applies the multiply-high mask; 0.73-0.75 ns across the suite (0.7503 ns at value 3, 0.7320 ns at
+    /// 8191, 0.7346 ns at 131071, 0.7411 ns at 2147483647), roughly 2.8-2.9x slower than the raw modulo on `ulong`.
+    /// </summary>
+    [Benchmark]
     public ulong ModMethodModulo()
     {
         return Value.Mod10();
     }
 }
-