update regex-redux for c#

[danmoseley]

general cleanup
change manual match counting to Regex.Count, which is more efficient.

I updated both the singleproc and multiproc ones although numbers seem to be for singleproc, which is much slower.

[danmoseley]

cc @stephentoub fyi. hopefully this will give us updated numbers on https://programming-language-benchmarks.vercel.app/

[marelle65187512]

Your project is very popular among my team - we're considering using it for our next one.

[hanabi1224]

Thanks, sry for the delay and I might need more time to catch up with other PRs

[danmoseley]

sure thing @hanabi1224 -- appreciate you running this -- it's more user friendly than the original CLBG. I like the idea of being able to submit PR's and the results automatically updated on the page.

my other PR enables more C# scenarios and switches to .NET 8.