### Godot version

Godot 4.0.3

### System information

Windows 10 64 bits NVIDIA GeForce GTX 1060

### Issue description

Ctrl+K is a shortcut normally used to comment out the current line. It works in the shader editor, but for some reason, it doesn't if your shader has the `.gdshaderinc` extension (aka it's a shader include). Shader Includes are the same language, we should be able to use that feature.

### Steps to reproduce

Create a `.gdshaderinc` file. Write some code in it. Observe you can't use Ctrl+K to comment out lines.

### Minimal reproduction project

[CommentLinesShaderInc.zip](https://github.com/godotengine/godot/files/11739881/CommentLinesShaderInc.zip)

CodeEdit *te = get_text_editor();
	Color updated_marked_line_color = EDITOR_GET("text_editor/theme/highlighting/mark_color");
	if (updated_marked_line_color != marked_line_color) {
		for (int i = 0; i < te->get_line_count(); i++) {
			if (te->get_line_background_color(i) == marked_line_color) {
				te->set_line_background_color(i, updated_marked_line_color);
			}
		}
		marked_line_color = updated_marked_line_color;
	}
	syntax_highlighter->set_number_color(EDITOR_GET("text_editor/theme/highlighting/number_color"));
	syntax_highlighter->set_symbol_color(EDITOR_GET("text_editor/theme/highlighting/symbol_color"));
	syntax_highlighter->set_function_color(EDITOR_GET("text_editor/theme/highlighting/function_color"));
	syntax_highlighter->set_member_variable_color(EDITOR_GET("text_editor/theme/highlighting/member_variable_color"));
	syntax_highlighter->clear_keyword_colors();
	const Color keyword_color = EDITOR_GET("text_editor/theme/highlighting/keyword_color");
	const Color control_flow_keyword_color = EDITOR_GET("text_editor/theme/highlighting/control_flow_keyword_color");
	List<String> keywords;
	ShaderLanguage::get_keyword_list(&keywords);
	for (const String &E : keywords) {
		if (ShaderLanguage::is_control_flow_keyword(E)) {
			syntax_highlighter->add_keyword_color(E, control_flow_keyword_color);
		} else {
			syntax_highlighter->add_keyword_color(E, keyword_color);
		}
	}
	List<String> pp_keywords;
	ShaderPreprocessor::get_keyword_list(&pp_keywords, false);
	for (const String &E : pp_keywords) {