feat: parse into a Document that keeps order and comments

Assisted-by: DeepSeek V4.1 Flash

decode_test.go

@@ -24,7 +24,7 @@ func TestSyntaxErrorMessage(t *testing.T) {
 }
 
 func TestParseRejectsInvalidUTF8(t *testing.T) {
-	_, err := Parse([]byte("v = \"\xff\"\n"))
+	_, err := ParseMap([]byte("v = \"\xff\"\n"))
 	if err == nil {
 		t.Fatal("expected a UTF-8 validation error")
 	}
@@ -130,7 +130,7 @@ func TestUnmarshalIntoNilAny(t *testing.T) {
 func TestParseContextHonoursCancellation(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
-	if _, err := ParseContext(ctx, []byte("a = 1\n")); !errors.Is(err, context.Canceled) {
+	if _, err := ParseMapContext(ctx, []byte("a = 1\n")); !errors.Is(err, context.Canceled) {
 		t.Fatalf("ParseContext returned %v, want context.Canceled", err)
 	}
 }
@@ -160,7 +160,7 @@ func TestContextRoundTrip(t *testing.T) {
 	in := []byte(`title = "x"
 count = 3
 `)
-	if _, err := ParseContext(context.Background(), in); err != nil {
+	if _, err := ParseMapContext(context.Background(), in); err != nil {
 		t.Fatalf("ParseContext: %v", err)
 	}
 	var out struct {
@@ -987,7 +987,7 @@ func TestDecoderMaxInputSize(t *testing.T) {
 		t.Errorf("err = %v, want it to name the limit", err)
 	}
 	// Parse carries the nesting default and no size limit.
-	if _, err := Parse(doc); err != nil {
+	if _, err := ParseMap(doc); err != nil {
 		t.Fatalf("parse: %v", err)
 	}
 }