Update README noting that the auto-generated stage factories include the available options in their docstring

Author: gsakkis

README.rst

@@ -80,14 +80,33 @@ Stage Objects
 - A stage can be instantiated by passing as keyword arguments the options
   applicable to the respective PDAL stage. For more on PDAL stages and their
   options, check the PDAL documentation on `Stage Objects <https://pdal.io/pipeline.html#stage-objects>`__.
-- The ``filename`` option of ``Readers`` and ``Writers`` as well as the ``type``
-  option of ``Filters`` can be passed positionally as the first argument.
-- The ``inputs`` option specifies a sequence of stages to be set as input to the
-  current stage. Each input can be either the string tag of another stage, or
-  the ``Stage`` instance itself.
-- The ``Reader``, ``Filter`` and ``Writer`` classes come with classmethods for
+
+  - The ``filename`` option of ``Readers`` and ``Writers`` as well as the ``type``
+    option of ``Filters`` can be passed positionally as the first argument.
+  - The ``inputs`` option specifies a sequence of stages to be set as input to the
+    current stage. Each input can be either the string tag of another stage, or
+    the ``Stage`` instance itself.
+- The ``Reader``, ``Filter`` and ``Writer`` classes come with static methods for
   all the respective PDAL drivers. For example, ``pdal.Filter.head()`` is a
-  shortcut for ``pdal.Filter(type="filters.head")``.
+  shortcut for ``pdal.Filter(type="filters.head")``. These methods are
+  auto-generated by introspecting ``pdal`` and the available options are
+  included in each method's docstring:
+
+.. code-block::
+
+    >>> help(pdal.Filter.head)
+    Help on function head in module pdal.pipeline:
+
+    head(**kwargs)
+        Return N points from beginning of the point cloud.
+
+        user_data: User JSON
+        log: Debug output filename
+        option_file: File from which to read additional options
+        where: Expression describing points to be passed to this filter
+        where_merge='auto': If 'where' option is set, describes how skipped points should be merged with kept points in standard mode.
+        count='10': Number of points to return from beginning.  If 'invert' is true, number of points to drop from the beginning.
+        invert='false': If true, 'count' specifies the number of points to skip from the beginning.
 
 Pipeline Objects
 ================

pdal/drivers.py

@@ -42,6 +42,7 @@ def factory(self) -> Callable[..., Stage]:
             factory = lambda **kwargs: self.type(type=self.name, **kwargs)
         factory.__name__ = self.short_name
         factory.__qualname__ = f"{self.type.__name__}.{self.short_name}"
+        factory.__module__ = self.type.__module__
         factory.__doc__ = self.description
         if self.options:
             factory.__doc__ += "\n\n"