* Added arg/return type handling.
* Added support for nested arg/return type in py::typing::List
* Added support for arg/return type in stl/filesystem
* Added tests for arg/return type in stl/filesystem and py::typing::List
* Added arg/return name to more py::typing classes
* Added arg/return type to Callable[...]
* Added tests for typing container classes (also nested)
* Changed typing classes to avoid using C++14 auto return type deduction.
* Fixed clang-tidy errors.
* Changed Enable to SFINAE
* Added test for Tuple[T, ...]
* Added RealNumber with custom caster for testing typing classes.
* Added tests for Set, Iterable, Iterator, Union, and Optional
* Added tests for Callable
* Fixed Callable with ellipsis test
* Changed TypeGuard/TypeIs to use return type (being the narrower type) + Tests
* Added test for use of fallback type name with stl vector
* Updated documentation.
* Fixed unnecessary constructor call in test.
* Fixed reference counting in example type caster.
* Fixed clang-tidy issues.
* Fix for clang-tidy
* Updated cast method to use pybind11 API rather than Python C API in custom caster example
* Updated load to use pybind11 API rather than Python C API in custom caster example
* Changed test of arg/return name to use pybind11 API instead of Python C API
* Updated code in adcanced/cast example and improved documentation text
* Fixed references in custom type caster docs
* Fixed wrong logical and operator in test
* Fixed wrong logical operator in doc example
* Added comment to test about `float` vs `float | int`
* Updated std::filesystem::path docs in cast/overview section
* Remove one stray dot.
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Co-authored-by: Ralf W. Grosse-Kunstleve <rgrossekunst@nvidia.com>