Add type caster for std::variant and other variant-like classes
diff --git a/docs/advanced/cast/overview.rst b/docs/advanced/cast/overview.rst
index 54c11a9..49781dc 100644
--- a/docs/advanced/cast/overview.rst
+++ b/docs/advanced/cast/overview.rst
@@ -144,6 +144,8 @@
+------------------------------------+---------------------------+-------------------------------+
| ``std::experimental::optional<T>`` | STL optional type (exp.) | :file:`pybind11/stl.h` |
+------------------------------------+---------------------------+-------------------------------+
+| ``std::variant<...>`` | Type-safe union (C++17) | :file:`pybind11/stl.h` |
++------------------------------------+---------------------------+-------------------------------+
| ``std::function<...>`` | STL polymorphic function | :file:`pybind11/functional.h` |
+------------------------------------+---------------------------+-------------------------------+
| ``std::chrono::duration<...>`` | STL time duration | :file:`pybind11/chrono.h` |