Report error diagnostic when a specific overload from a single template would be generated multiple times

[FramePerfection]

This adds an error diagnostic when a single template delegate in combination with its respective TemplateGenerator attribute would generate the same overload multiple times.

For exmample, the following code would generate an error diagnostic:

[ChaosGenerators.TemplateGenerator(
    "=> new System.Tuple<T1, T2, T3>(v1, v2, v3[0]);",
    typeof(float), typeof(int), typeof(string),
    typeof(float), null, typeof(string),
    typeof(float), null, typeof(string), // this would generate the same overload as the line above
    null, typeof(int), null
    )]
internal delegate System.Tuple<T1, T2, T3> _Test<T1, T2, T3>(ref T1 v1, ref readonly T2 v2, params T3[] v3);

It may be better to use ChaosUtil's Array equality checks rather than the somewhat scuffed OverloadComparer solution, which would then operate on a TemplateParameter type (or similar in name) replacing the anonymous ((Regex, string), ITypeSymbol) type, hence the draft label.

[InsanityCode]

The overall changes seem fine to me.

I implemented your suggestions regarding the elimination of anonymous types and using ChaosUtil.Primitives (see #4), so if these changes meet your expectations, please merge them into this PR.

As mentioned here, I think raising a warning would be enough, but changing the error to a warning can be done later.

[InsanityCode]

👍