### 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)

String iterative = p_string;
	int pass_count = 0;
	bool expanded = true;
	while (expanded) {
		expanded = false;
		
		for (const RBMap<String, Define *>::Element *E = state->defines.front(); E; E = E->next()) {
			if (expand_macros_once(iterative, p_line, E, iterative)) {
				expanded = true;
			}
		}
		pass_count++;
		if (pass_count > 50) {
			set_error(RTR("Macro expansion limit exceeded."), p_line);
			break;
		}
	}
	r_expanded = iterative;
	if (!state->error.is_empty()) {
		return FAILED;
	}
	return OK;
}
bool ShaderPreprocessor::expand_macros_once(const String &p_line, int p_line_number, const RBMap<String, Define *>::Element *p_define_pair, String &r_expanded) {