C# 11: Checked operator support.

[michaelnebel]

In this PR we

• Introduce library support for checked operators (extractor support had already been implemented).
• Use the stored method name as the function name of an operator instead of hardcoding the name in the QL library code.
• Add appropriate tests.

There is compile time check that ensures that a regular operator i always defined, when a checked variant is defined.

public class Number
{
    public int Value { get; }

    public static Number operator checked +(Number n1, Number n2) =>
        new Number(checked(n1.Value + n2.Value));

    public static Number operator +(Number n1, Number n2) =>
        new Number(n1.Value + n2.Value);
}

Should we structure this differently: Eg AddOperator could contains all (both checked and regular operators and then CheckedAddOperator could extend AddOperator?

Outstanding tasks

• Run DCA

[hvitved]

Excellent!

[michaelnebel]

DCA looks good!