### 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 (index < size) {
		const char32_t c = code[index++];
		const Token t = ShaderPreprocessor::Token(c, line);
		switch (c) {
			case ' ':
			case '\t':
				skip_whitespace();
				return ShaderPreprocessor::Token(' ', line);
			case '\n':
				line++;
				return t;
			default:
				return t;
		}
	}
	return ShaderPreprocessor::Token(char32_t(0), line);
}
ShaderPreprocessor::Tokenizer::Tokenizer(const String &p_code) {
	code = p_code;
	line = 0;
	index = 0;
	size = code.size();
}
String ShaderPreprocessor::CommentRemover::get_error() const {
	if (comments_open != 0) {
		return "Block comment mismatch";
	}
	return "";
}
int ShaderPreprocessor::CommentRemover::get_error_line() const {