Add a fixer for CA2200

[goyzhang]

Replace throw e; to throw;
Reference #692

[mavasani]

Couple of comments:

1. You don't need to get the first diagnostic or use it's span
2. Please add a null check for nodeToReplace

            var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
            var nodeToReplace = root.FindNode(context.Span);
            if (nodeToReplace == null)
            {
                return;
            }

            context.RegisterCodeFix(
                CodeAction.Create(...),
                context.Diagnostics);

[goyzhang]

Uh, Ok, I just got it from the boilerplate https://docs.microsoft.com/en-us/dotnet/csharp/roslyn-sdk/tutorials/how-to-write-csharp-analyzer-code-fix and it does the job as well. I will modify it.