go: stringer: type: interface: one implementation for all

[AmitKumarDas]

• https://github.com/google/go-cmp/blob/master/cmp/compare_test.go

  
  type Stringer string

func newStringer(s string) fmt.Stringer { return (*Stringer)(&s) } func (s Stringer) String() string { return string(s) }