### Godot version

v4.0.beta15.official [4fa6edc88]

### System information

Windows 10 (10.0.19045 Build 19045) | Forward+ | Vulkan API 1.3.206 | AMD Radeon RX 6800 XT

### Issue description

If there is a function with arguments within a `.gdshaderinc` file, then this function can not be used in other shaders that include this via a relative include. The error in the other shaders is "Too many arguments for "example()" call. Expected at most 0 but received 1". Using an absolute path for the include resolves the error.

**Note:** The relative include *does* work in the special case of both files being in the project root.

### Steps to reproduce

1. Put a shader and a shader-include file into a subdirectory
2. Write a function with arguments in the shader-include file
3. Include that file in the shader
4. Try to use the function

### Minimal reproduction project

[shader-include-bug.zip](https://github.com/godotengine/godot/files/10508745/shader-include-bug.zip)

const int line = p_tokenizer->get_line();
	int nesting = 0;
	while (true) {
		p_tokenizer->advance('#');
		String id = p_tokenizer->peek_identifier();
		if (id.is_empty()) {
			break;
		}
		if (nesting == 0) {
			for (int i = 0; i < p_directives.size(); i++) {
				if (p_directives[i] == id) {
					p_tokenizer->backtrack('#');
					return id;
				}
			}
		}
		if (id == "ifdef" || id == "ifndef" || id == "if") {
			nesting++;
		} else if (id == "endif") {
			nesting--;
		}
	}
	set_error(RTR("Can't find matching branch directive."), line);
	return "";
}
void ShaderPreprocessor::add_to_output(const String &p_str) {