`Equatable` is redundant with `EquatableMixin`

[Albert221]

I am reopening #160, as it was supposed to be fixed with macros, but we won't have macros. And the former issue wasn't reopened.

Below is the copied original post from @shilangyu:

Is your feature request related to a problem? Please describe.

When choosing which one to use (Equatable or EquatableMixin) there is no benefit of choosing Equatable (or I am failing to see one) over the mixin version. This duplicates the API for no clear reason to me.

Describe the solution you'd like

Removing the non-mixin version. This simplifies this package, docs, and usage.

Additional context

During code reviews I often have to tell people to use the mixin version instead, since it is more extensible (for example will allow in the future to extend some other class).

If I am missing some advantage that the class version has, please let me know what that is and feel free to close this issue.

[ricardodalarme]

Hey @felangel, any updates on that?

[felangel]

Planning to spend some time reworking the v3.0.0 release candidate to incorporate this change this week. Apologies for the delay!