style: ID instead of Id

internal/registry/repr.go

@@ -4,7 +4,7 @@ type Repr interface {
 	// Id returns to name of the objects underlying representation. If is
 	// assumed that if two Repr objects have the same Id(), they share the same
 	// representation.
-	Id() string
+	ID() string
 
 	Data() any
 }
@@ -14,7 +14,7 @@ type baseRepr struct {
 	data any
 }
 
-func (r baseRepr) Id() string { return r.id }
+func (r baseRepr) ID() string { return r.id }
 
 func (r baseRepr) Data() any { return r.data }