Doc update.

doc/stages/writer_opts.rst

@@ -0,0 +1,13 @@
+where
+    An :ref:`expression <PDAL expression>` that limits points passed to a filter.
+    Points that don't pass the
+    expression skip the stage but are available to subsequent stages in a pipeline.
+    [Default: no filtering]
+
+where_merge
+    A strategy for merging points skipped by a '`where'` option when running in standard mode.
+    If ``true``, the skipped points are added to the first point view returned by the skipped
+    filter. If ``false``, skipped points are placed in their own point view. If ``auto``,
+    skipped points are merged into the returned point view provided that only one point view
+    is returned and it has the same point count as it did when the filter was run.
+    [Default: ``auto``]

doc/stages/writers.draco.rst

@@ -72,7 +72,7 @@ quantization
     "GENERIC": 8
 }
 
-
+.. include:: writer_opts.rst
 
 .. _PDAL's Type specification: https://github.com/PDAL/PDAL/blob/master/pdal/DimUtil.hpp
-.. _Draco: https://github.com/google/draco
+.. _Draco: https://github.com/google/draco

doc/stages/writers.raster.rst

@@ -89,3 +89,4 @@ nodata
     [Default: depends on the data_type_.  -9999 for double, float, int and short, 9999 for
     unsigned int and unsigned short, 255 for unsigned char and -128 for char]
 
+.. include:: writer_opts.rst