Document some additional C++ auto-conversions (GH-4090)

docs/src/userguide/wrapping_CPlusPlus.rst

@@ -331,19 +331,27 @@ arguments) or by an explicit cast, e.g.:
 
 The following coercions are available:
 
-+------------------+----------------+-----------------+
-| Python type =>   | *C++ type*     | => Python type  |
-+==================+================+=================+
-| bytes            | std::string    | bytes           |
-+------------------+----------------+-----------------+
-| iterable         | std::vector    | list            |
-+------------------+----------------+-----------------+
-| iterable         | std::list      | list            |
-+------------------+----------------+-----------------+
-| iterable         | std::set       | set             |
-+------------------+----------------+-----------------+
-| iterable (len 2) | std::pair      | tuple (len 2)   |
-+------------------+----------------+-----------------+
++------------------+------------------------+-----------------+
+| Python type =>   | *C++ type*             | => Python type  |
++==================+========================+=================+
+| bytes            | std::string            | bytes           |
++------------------+------------------------+-----------------+
+| iterable         | std::vector            | list            |
++------------------+------------------------+-----------------+
+| iterable         | std::list              | list            |
++------------------+------------------------+-----------------+
+| iterable         | std::set               | set             |
++------------------+------------------------+-----------------+
+| iterable         | std::unordered_set     | set             |
++------------------+------------------------+-----------------+
+| mapping          | std::map               | dict            |
++------------------+------------------------+-----------------+
+| mapping          | std::unordered_map     | dict            |
++------------------+------------------------+-----------------+
+| iterable (len 2) | std::pair              | tuple (len 2)   |
++------------------+------------------------+-----------------+
+| complex          | std::complex           | complex         |
++------------------+------------------------+-----------------+
 
 All conversions create a new container and copy the data into it.
 The items in the containers are converted to a corresponding type