DotNetStringBuilder is faster

[alex-jitbit]

Seems like you removed the DotNetStringBuilder bench, but after adding it back this is what I get:

BenchmarkDotNet v0.13.12, Windows 11 (10.0.22631.3593/23H2/2023Update/SunValley3)
AMD Ryzen 7 7800X3D, 1 CPU, 16 logical and 8 physical cores
.NET SDK 8.0.300
  [Host]   : .NET 8.0.5 (8.0.524.21615), X64 RyuJIT AVX-512F+CD+BW+DQ+VL+VBMI
  ShortRun : .NET 8.0.5 (8.0.524.21615), X64 RyuJIT AVX-512F+CD+BW+DQ+VL+VBMI

Job=ShortRun  IterationCount=3  LaunchCount=1
WarmupCount=3

| Method              | Mean      | Error    | StdDev   | Gen0   | Gen1   | Allocated |
|-------------------- |----------:|---------:|---------:|-------:|-------:|----------:|
| ValueStringBuilder  | 176.37 ns | 62.05 ns | 3.401 ns | 0.0250 |      - |   1.23 KB |
| DotNetStringBuilder |  97.29 ns | 35.04 ns | 1.920 ns | 0.0315 | 0.0001 |   1.54 KB |