### 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
int servpos = find("/", basepos + 1);
			if (servpos == -1) {
				servpos = find("\\", basepos + 1);
			}
			if (servpos != -1) {
				end = servpos + 1;
			}
		}
	}
	// 
	if (end == 0) {
		if (begins_with("/")) {
			end = 1;
		}
	}
	 rs;
	 base;
	if (end != 0) {
		rs = substr(end, length());
		base = substr(0, end);
	} else {
		rs = *this;
	}
	int sep = MAX(rs.rfind("/"), rs.rfind("\\"));
	if (sep == -1) {
		return base;
	}
	return base + rs.substr(0, sep);
}
 ::get_file() const {