chore: Added suppression attributes to CA1822

[nikcio]

Following #690 I've now added suppression attributes to the methods we decided not to make static.

Adds to #663

I also had another look at This issue and found that the reason this caused problems is because I forgot to change the this. to BasicModelBE. in the Score method. But I don't know if this is moving too far away from the original code?

The change would be:

public override sealed float Score(BasicStats stats, float tfn)
{
    double F = stats.TotalTermFreq + 1 + tfn;
    // approximation only holds true when F << N, so we use N += F
    double N = F + stats.NumberOfDocuments;
    return (float)(-SimilarityBase.Log2((N - 1) * Math.E) + BasicModelBE.F(N + F - 1, N + F - tfn - 2) - BasicModelBE.F(F, F - tfn));
}
/// <summary>
/// The <em>f</em> helper function defined for <em>B<sub>E</sub></em>. </summary>
private static double F(double n, double m) // LUCENENET: CA1822: Mark members as static
{
    return (m + 0.5) * SimilarityBase.Log2(n / m) + (n - m) * SimilarityBase.Log2(n);
}

[NightOwl888]

I also had another look at This issue and found that the reason this caused problems is because I forgot to change the this. to BasicModelBE. in the Score method. But I don't know if this is moving too far away from the original code?

The change would be:

public override sealed float Score(BasicStats stats, float tfn)
{
    double F = stats.TotalTermFreq + 1 + tfn;
    // approximation only holds true when F << N, so we use N += F
    double N = F + stats.NumberOfDocuments;
    return (float)(-SimilarityBase.Log2((N - 1) * Math.E) + BasicModelBE.F(N + F - 1, N + F - tfn - 2) - BasicModelBE.F(F, F - tfn));
}
/// <summary>
/// The <em>f</em> helper function defined for <em>B<sub>E</sub></em>. </summary>
private static double F(double n, double m) // LUCENENET: CA1822: Mark members as static
{
    return (m + 0.5) * SimilarityBase.Log2(n / m) + (n - m) * SimilarityBase.Log2(n);
}

 
  /** The <em>f</em> helper function defined for <em>B<sub>E</sub></em>. */
  private final double f(double n, double m) {
    return (m + 0.5) * log2(n / m) + (n - m) * log2(n);
  }

In the original code the function f was lowercase. I first thought that forced them to use uppercase F as a varible name. But, judging by the documentation and comments, the capital F variable name seems to be a math thing, and therefore intentional.

Let's revert F(double n, double m) to an instance method and add the SuppressMessage attribute to the F(double n, double m) method.

We should also add the [MethodImpl(MethodImplOptions.AggressiveInlining)] attribute to the F(double n, double m) method to prompt the compiler to inline this math in the Score function, which will give a similar benefit to making the method static.

I have also opened #694 which is related, but should be done in a separate PR since it goes beyond this one class.

[NightOwl888]

@nikcio - Forgot to go through the review process when I left my last comment.

[nikcio]

The PR has now been updated after the comment above