### 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
break;
				}
				case 's': { // 
					if (value_index >= values.size()) {
						return "not enough arguments for format string";
					}
					 str = values[value_index];
					// 
					if (left_justified) {
						str = str.rpad(min_chars);
					} else {
						str = str.lpad(min_chars);
					}
					formatted += str;
					++value_index;
					in_format = false;
					break;
				}
				case 'c': {
					if (value_index >= values.size()) {
						return "not enough arguments for format string";
					}
					// 
					 str;
					if (values[value_index].is_num()) {
						int value = values[value_index];
						if (value < 0) {
							return "unsigned integer is lower than minimum";
						} else if (value >= 0xd800 && value <= 0xdfff) {
							return "unsigned integer is invalid Unicode character";