### 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
}
		cstr_size--;
		p_utf8++;
	}
	if (skip) {
		*(dst++) = 0x20;
	}
	if (decode_) {
		return ERR_INVALID_DATA;
	} else if (decode_error) {
		return ERR_PARSE_ERROR;
	} else {
		return OK;
	}
}
Char ::utf8() const {
	int l = length();
	if (!l) {
		return Char();
	}
	const char32_t *d = &operator[](0);
	int fl = 0;
	for (int i = 0; i < l; i++) {
		uint32_t c = d[i];
		if (c <= 0x7f) { // 
			fl += 1;
		} else if (c <= 0x7ff) { // 
			fl += 2;
		} else if (c <= 0xffff) { // 
			fl += 3;