### 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)

sl.complete(code, comp_info, r_options, calltip);
		get_text_editor()->set_code_hint(calltip);
		return;
	}
	_check_shader_mode();
	comp_info.functions = ShaderTypes::get_singleton()->get_functions(RenderingServer::ShaderMode(shader->get_mode()));
	comp_info.render_modes = ShaderTypes::get_singleton()->get_modes(RenderingServer::ShaderMode(shader->get_mode()));
	comp_info.shader_types = ShaderTypes::get_singleton()->get_types();
	sl.complete(code, comp_info, r_options, calltip);
	get_text_editor()->set_code_hint(calltip);
}
void ShaderTextEditor::_validate_script() {
	emit_signal(SNAME("script_changed")); 
	String code;
	if (shader.is_valid()) {
		_check_shader_mode();
		code = shader->get_code();
	} else {
		code = shader_inc->get_code();
	}
	ShaderPreprocessor preprocessor;
	String code_pp;
	String error_pp;
	List<ShaderPreprocessor::FilePosition> err_positions;
	List<ShaderPreprocessor::Region> regions;
	String filename;
	if (shader.is_valid()) {
		filename = shader->get_path();
	} else if (shader_inc.is_valid()) {
		filename = shader_inc->get_path();