### Godot version

4.0.3

### System information

Win7

### Issue description

#if and #else highlighted with the color same as if and else shader statement:

![image](https://github.com/godotengine/godot/assets/28286958/c2d58151-d6d2-4305-b4da-36e76e316caf)


### Steps to reproduce

1. Create shader
2. Add #if and #else

### Minimal reproduction project

N/A
Dictionary color_map;
	for (const Point2i &region : disabled_branch_regions) {
		if (p_line >= region.x && p_line <= region.y) {
			Dictionary highlighter_info;
			highlighter_info["color"] = disabled_branch_color;
			color_map[0] = highlighter_info;
			return color_map;
		}
	}
	return CodeHighlighter::_get_line_syntax_highlighting_impl(p_line);
}
void GDShaderSyntaxHighlighter::add_disabled_branch_region(const Point2i &p_region) {
	ERR_FAIL_COND(p_region.x < 0);
	ERR_FAIL_COND(p_region.y < 0);
	for (int i = 0; i < disabled_branch_regions.size(); i++) {
		ERR_FAIL_COND_MSG(disabled_branch_regions[i].x == p_region.x, "Branch region with a start line '" + itos(p_region.x) + "' already exists.");
	}
	Point2i disabled_branch_region;
	disabled_branch_region.x = p_region.x;
	disabled_branch_region.y = p_region.y;
	disabled_branch_regions.push_back(disabled_branch_region);
	clear_highlighting_cache();
}
void GDShaderSyntaxHighlighter::clear_disabled_branch_regions() {