### Godot version

4.1.1

### System information

linux

### Issue description

The `"%+f"` format adds a `+` sign in front of positive numbers. If you try to format `-0.0`, it breaks and displays both a `+` and a `-`.

### Steps to reproduce

```gdscript
@tool
extends EditorScript

func _run() -> void:
    print("%+f" % -0.0)
```

### Minimal reproduction project

see above
args.clear();
	args.push_back(-99.99);
	ERR_PRINT_OFF; 
	output = format.sprintf(args, &error);
	ERR_PRINT_ON;
	REQUIRE(error == false);
	CHECK(output == String("fish -99.990000  frog"));
	
	
	format = "fish %v frog";
	args.clear();
	args.push_back(Variant(Vector2(19.99, 1.00)));
	output = format.sprintf(args, &error);
	REQUIRE(error == false);
	CHECK(output == String("fish (19.990000, 1.000000) frog"));
	
	format = "fish %v frog";
	args.clear();
	args.push_back(Variant(Vector3(19.99, 1.00, -2.05)));
	output = format.sprintf(args, &error);
	REQUIRE(error == false);
	CHECK(output == String("fish (19.990000, 1.000000, -2.050000) frog"));
	
	format = "fish %v frog";
	args.clear();
	args.push_back(Variant(Vector4(19.99, 1.00, -2.05, 5.5)));
	output = format.sprintf(args, &error);
	REQUIRE(error == false);
	CHECK(output == String("fish (19.990000, 1.000000, -2.050000, 5.500000) frog"));