### 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
err = no_cr.parse_utf8(base.utf8().get_data(), -1, true); 
	CHECK(err == OK);
	CHECK(no_cr == base.replace("\r", ""));
}
TEST_CASE("[String] Invalid UTF8 (non-standard)") {
	ERR_PRINT_OFF
	static const uint8_t u8str[] = { 0x45, 0xE3, 0x81, 0x8A, 0xE3, 0x82, 0x88, 0xE3, 0x81, 0x86, 0xF0, 0x9F, 0x8E, 0xA4, 0xF0, 0x82, 0x82, 0xAC, 0xED, 0xA0, 0x81, 0 };
	
	static const char32_t u32str[] = { 0x45, 0x304A, 0x3088, 0x3046, 0x1F3A4, 0x20AC, 0xFFFD, 0 };
	String s;
	Error err = s.parse_utf8((const char *)u8str);
	CHECK(err == ERR_INVALID_DATA);
	CHECK(s == u32str);
	CharString cs = (const char *)u8str;
	CHECK(String::utf8(cs) == s);
	ERR_PRINT_ON
}
TEST_CASE("[String] Invalid UTF8 (unrecoverable)") {
	ERR_PRINT_OFF
	static const uint8_t u8str[] = { 0x45, 0xE3, 0x81, 0x8A, 0x8F, 0xE3, 0xE3, 0x98, 0x8F, 0xE3, 0x82, 0x88, 0xE3, 0x81, 0x86, 0xC0, 0x80, 0xF0, 0x9F, 0x8E, 0xA4, 0xF0, 0x82, 0x82, 0xAC, 0xED, 0xA0, 0x81, 0 };
	
	static const char32_t u32str[] = { 0x45, 0x304A, 0xFFFD, 0xFFFD, 0xFFFD, 0xFFFD, 0x3088, 0x3046, 0xFFFD, 0x1F3A4, 0x20AC, 0xFFFD, 0 };
	String s;
	Error err = s.parse_utf8((const char *)u8str);
	CHECK(err == ERR_INVALID_DATA);
	CHECK(s == u32str);
	CharString cs = (const char *)u8str;
	CHECK(String::utf8(cs) == s);
	ERR_PRINT_ON
}