Add type[T] support to typing.h (#5166)

* add type[T]

* style: pre-commit fixes

* fix merge

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: InvincibleRMC

include/pybind11/typing.h

@@ -63,6 +63,11 @@ class Callable<Return(Args...)> : public function {
     using function::function;
 };
 
+template <typename T>
+class Type : public type {
+    using type::type;
+};
+
 template <typename... Types>
 class Union : public object {
     using object::object;
@@ -131,6 +136,11 @@ struct handle_type_name<typing::Callable<Return(Args...)>> {
           + const_name("], ") + make_caster<retval_type>::name + const_name("]");
 };
 
+template <typename T>
+struct handle_type_name<typing::Type<T>> {
+    static constexpr auto name = const_name("type[") + make_caster<T>::name + const_name("]");
+};
+
 template <typename... Types>
 struct handle_type_name<typing::Union<Types...>> {
     static constexpr auto name = const_name("Union[")

tests/test_pytypes.cpp

@@ -844,6 +844,7 @@ TEST_SUBMODULE(pytypes, m) {
     m.def("annotate_iterator_int", [](const py::typing::Iterator<int> &) {});
     m.def("annotate_fn",
           [](const py::typing::Callable<int(py::typing::List<py::str>, py::str)> &) {});
+    m.def("annotate_type", [](const py::typing::Type<int> &) {});
 
     m.def("annotate_union",
           [](py::typing::List<py::typing::Union<py::str, py::int_, py::object>> l,

tests/test_pytypes.py

@@ -957,6 +957,10 @@ def test_fn_annotations(doc):
     )
 
 
+def test_type_annotation(doc):
+    assert doc(m.annotate_type) == "annotate_type(arg0: type[int]) -> None"
+
+
 def test_union_annotations(doc):
     assert (
         doc(m.annotate_union)