### 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)

if (index < size) {
		return code[index];
	}
	return 0;
}
int ShaderPreprocessor::Tokenizer::consume_line_continuations(int p_offset) {
	int skips = 0;
	for (int i = index + p_offset; i < size; i++) {
		char32_t c = code[i];
		if (c == '\\') {
			if (i + 1 < size && code[i + 1] == '\n') {
				
				add_generated(Token('\n', line));
				line++;
				skips++;
				i = i + 2;
				index = i;
			} else {
				break;
			}
		} else if (!is_whitespace(c)) {
			break;
		}
	}
	return skips;
}
LocalVector<ShaderPreprocessor::Token> ShaderPreprocessor::Tokenizer::advance(char32_t p_what) {