### 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)

shader_editor->update_editor_settings();
	shader_editor->get_text_editor()->add_theme_constant_override("line_spacing", EDITOR_GET("text_editor/appearance/whitespace/line_spacing"));
	shader_editor->get_text_editor()->set_draw_breakpoints_gutter(false);
	shader_editor->get_text_editor()->set_draw_executing_lines_gutter(false);
	trim_trailing_whitespace_on_save = EDITOR_GET("text_editor/behavior/files/trim_trailing_whitespace_on_save");
}
void TextShaderEditor::_show_warnings_panel(bool p_show) {
	warnings_panel->set_visible(p_show);
}
void TextShaderEditor::_warning_clicked(Variant p_line) {
	if (p_line.get_type() == Variant::INT) {
		shader_editor->get_text_editor()->set_caret_line(p_line.operator int64_t());
	}
}
void TextShaderEditor::_bind_methods() {
	ClassDB::bind_method("_show_warnings_panel", &TextShaderEditor::_show_warnings_panel);
	ClassDB::bind_method("_warning_clicked", &TextShaderEditor::_warning_clicked);
	ADD_SIGNAL(MethodInfo("validation_changed"));
}
void TextShaderEditor::ensure_select_current() {
}
void TextShaderEditor::goto_line_selection(int p_line, int p_begin, int p_end) {
	shader_editor->goto_line_selection(p_line, p_begin, p_end);
}
void TextShaderEditor::_project_settings_changed() {
	_update_warnings(true);
}
void TextShaderEditor::_update_warnings(bool p_validate) {