Companion object containing a few universally known
Eql instances involving primitive types or the Null type are handled directly in
the compiler (see Implicits.synthesizedEq), so they are not included here.
A fall-back instance to compare values of any types.
Even though this method is not declared a delegate, the compiler will
synthesize implicit arguments as solutions to
Eql[T, U] queries if
the rules of multiversal equality require it.