Give maxLen its own literal and repeats MaxRepeat; arg errors name the spelling and the range; write's comment says what Flush reports; assert 64-bit at compile time

node.go

@@ -288,8 +288,8 @@ func repeatOf(m map[string]any) (int, error) {
 	if r == 1 {
 		return 0, fmt.Errorf("repeat 1 is the default, so it has no effect; drop it")
 	}
-	if r > maxLen { // caps the renders one repeat asks for; checkRepeatReach bounds what nested ones multiply to
-		return 0, fmt.Errorf("repeat %v exceeds the maximum %d", rv, maxLen)
+	if r > MaxRepeat { // caps the renders one repeat asks for; checkRepeatReach bounds what nested ones multiply to
+		return 0, fmt.Errorf("repeat %v exceeds the maximum %d", rv, MaxRepeat)
 	}
 	return int(r), nil
 }