Work on #74: allow customizing whether the == and != operators are generated for classes

[fraluderin]

Proposed draft implementation: added parameter OverrideEqualityOperators in EquatableAttribute to customize equality operators override behavior; updated ClassEqualityGenerator to observe OverrideEqualityOperators parameter; added test cases BaseEqualityWithoutOperators

[diegofrata]

Hi @fraluderin. It looks as this PR was based off main. There has some significant rework in the the develop branch for version 4.0 which I just released today. This will need a rebase before it can be reviewed.

[fraluderin]

Hi @diegofrata, no problem.
I can rebase in the next few days.

I'll ask if I’m in doubt.

[diegofrata]

One concern is that OverrideEqualityOperators correctly only works on classes and does nothing for structs and records. I think this needs to be quite clear in the docs but also it would be useful to have an analyzer that warns the user that setting it to false on a struct/record does nothing.

[osexpert]

"One concern is that OverrideEqualityOperators correctly only works on classes and does nothing for structs and records"
Maybe it could be solved by rephrasing it, eg. GenerateClassEqualityOperators = true (default)

[diegofrata]

@osexpert I think that would do, but an analyzer is always a good call!