Cache the collected type information in getSourceLocation

[Numpsy]

refs #517

Just having a go at the suggestion in #517 (comment)

I've tried a local build with a couple of my own projects in Visual Studio 2022 and it seems to still work and be a tad faster, but the test discovery only takes a few seconds for those anyway so it's a small difference.

[TheAngryByrd]

If you want a an example to test. FsToolkit.ErrorHandling.Tests. Takes my machine about a little over ~20 to run with dotnet test but dotnet run is about 200ms.

YoloDev does have an upper bound for Expecto (>= 10.2.1 && < 11.0.0). Are you using another way or did you do a custom build of that as well?

[Numpsy]

Are you using another way or did you do a custom build of that as well?

I'm using a custom build (theres one at https://www.nuget.org/packages/Beardmouse.Expecto.Testing actually)

If you want a an example to test. FsToolkit.ErrorHandling.Tests.

With that, I get

Test summary: total: 1630, failed: 0, succeeded: 1622, skipped: 8, duration: 47.4s

with the current FsToolkit.ErrorHandling source, and

Test summary: total: 1630, failed: 0, succeeded: 1622, skipped: 8, duration: 3.7s

with it changed to use Expecto from this PR (so I'm not sure if the difference is just this change, or if it's picking up any other improvements in V11 as well)

For comparison, dotnet run takes barely over 1 second in either case

[farlee2121]

Dang. That is substantial.
The code looks good to me if you think it's ready