### 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)

while (is_char_space(peek())) {
		next();
	}
}
bool ShaderPreprocessor::Tokenizer::consume_empty_line() {
	
	return tokens_to_string(advance('\n')).strip_edges().size() == 0;
}
String ShaderPreprocessor::Tokenizer::get_identifier(bool *r_is_cursor, bool p_started) {
	if (r_is_cursor != nullptr) {
		*r_is_cursor = false;
	}
	LocalVector<char32_t> text;
	while (true) {
		char32_t c = peek();
		if (c == '\\' && consume_line_continuations(0) > 0) {
			continue;
		}
		if (is_char_end(c) || c == '(' || c == ')' || c == ',' || c == ';') {
			break;
		}
		if (is_whitespace(c) && p_started) {
			break;