Update porous media inputs from MR 1400 (!106)

docs/source_docs/user_guide/inputs/porous_media_defs.rst

@@ -20,7 +20,7 @@ The following inputs are defined using the ``pm`` prefix.
 +==========================+==============================================================================+==========+===========+
 | regions                  | Regions used to define porous media.                                         | String   |  None     |
 +--------------------------+------------------------------------------------------------------------------+----------+-----------+
-| [region].fluid.volfrac   | Fluid volume fraction of the porous media region.                            |  Real    |  None     |
+| [region].volfrac         | Solids volume fraction of the porous media region.                           |  Real    |  None     |
 +--------------------------+------------------------------------------------------------------------------+----------+-----------+
 | [region].c1              | Porous media permeabilty constant for the source term in fluid               |  Real    |  None     |
 |                          | momentum equation.                                                           |          |           |
@@ -28,3 +28,5 @@ The following inputs are defined using the ``pm`` prefix.
 | [region].c2              | Porous media inertial resistance factor for the source term in fluid         |  Real    |  None     |
 |                          | momentum equation.                                                           |          |           |
 +--------------------------+------------------------------------------------------------------------------+----------+-----------+
+| [region].allow_particles | Allow particles to flow through the porous media region.                     |  Int     |    0      |
++--------------------------+------------------------------------------------------------------------------+----------+-----------+