Change charListToString to use String.Create

[Numpsy]

Just a thought I had after running a run of FSharpLint over one of my projects thought the Visual Studio memory profiler. It's quite trivial in the overall schema of things, but in case anyone is interested.

I noticed that charListToString was creating quite a large number of strings:

And I wondered if String.Create could be used to reduce the number of temporary strings. Doing so got

The actual amounts of memory here are rather small compared to total memory because the strings are tine -

Before

| Method      | Mean    | Error    | StdDev   | Gen0        | Gen1       | Gen2      | Allocated  |
|------------ |--------:|---------:|---------:|------------:|-----------:|----------:|-----------:|
| LintProject | 3.983 s | 0.1033 s | 0.2964 s | 167000.0000 | 22000.0000 | 1000.0000 | 1008.65 MB |

After

| Method      | Mean    | Error    | StdDev   | Gen0        | Gen1       | Gen2      | Allocated  |
|------------ |--------:|---------:|---------:|------------:|-----------:|----------:|-----------:|
| LintProject | 3.916 s | 0.1088 s | 0.3088 s | 167000.0000 | 22000.0000 | 1000.0000 | 1007.31 MB |

But the change is also small so maybe it's still useful.

[knocte]

Not a fan of the <- operator TBH, maybe we can get similar gains by just using StringBuilder?

[Numpsy]

String.Create is supposed to allocate less than StringBuilder, but I haven't tried testing that here

[Numpsy]

Current .NET versions have built in CopyTo functions to copy List and Array into a Span, but I don't think there is anything built in to do the same with FSharpList. Would it be useful to add a local extension method rather than doing the work inline, which could be more reusable elsewhere?

[knocte]

Let's see the implementation of that?