chore: add GoString method to platform.ID

While debugging, I was printing out some structs with %#v and found that
Go would format the structs' IDs as uint64s instead of with the String
method. That behavior needlessly made my debugging more difficult.

Before, %#v would format a type with an ID like:

    {ID:0x2def021097c6000}

After:

    {ID:"02def021097c6000"}

They look similar, but a search for the string ID would not match the
uint64 default formatting.

id.go

@@ -111,6 +111,14 @@ func (i ID) String() string {
 	return string(enc)
 }
 
+// GoString formats the ID the same as the String method.
+// Without this, when using the %#v verb, an ID would be printed as a uint64,
+// so you would see e.g. 0x2def021097c6000 instead of 02def021097c6000
+// (note the leading 0x, which means the former doesn't show up in searches for the latter).
+func (i ID) GoString() string {
+	return `"` + i.String() + `"`
+}
+
 // UnmarshalJSON implements JSON unmarshaller for IDs.
 func (i *ID) UnmarshalJSON(b []byte) error {
 	if b[0] == '"' {

id_test.go

@@ -3,6 +3,7 @@ package platform_test
 import (
 	"bytes"
 	"encoding/json"
+	"fmt"
 	"reflect"
 	"testing"
 
@@ -193,6 +194,24 @@ func TestValid(t *testing.T) {
 	}
 }
 
+func TestID_GoString(t *testing.T) {
+	type idGoStringTester struct {
+		ID platform.ID
+	}
+	var x idGoStringTester
+
+	const idString = "02def021097c6000"
+	if err := x.ID.DecodeFromString(idString); err != nil {
+		t.Fatal(err)
+	}
+
+	sharpV := fmt.Sprintf("%#v", x)
+	want := `platform_test.idGoStringTester{ID:"` + idString + `"}`
+	if sharpV != want {
+		t.Fatalf("bad GoString: got %q, want %q", sharpV, want)
+	}
+}
+
 func BenchmarkIDEncode(b *testing.B) {
 	var id platform.ID
 	id.DecodeFromString("5ca1ab1eba5eba11")