Diagnostic CodeFix for CS1737/BC30202: Optional parameters must appear after all required parameters

[MaStr11]

Steps to Reproduce:

public class C {
    public void M(int i1 = 1, int i2)  // CS1737: Optional parameters must appear after all required parameters
    {
    }
}

Expected Behavior:

Offer fix: "Make 'i2' optional"

public class C {
    public void M(int i1 = 1, int i2 = 0) 
    {
    }
}

Related diagnostic id in VB: BC30202: 'Optional' expected. (and maybe BC30812: Optional parameters must specify a default value. can be fixed by this code fixer too).

Related #23326.