Corrected small grammatical mistakes in few files of docs.

docs/source/output.rst

@@ -105,7 +105,7 @@ Within each individual ``tl`` group are the following datasets:
 Snapshots
 ---------
 
-Snapshot files contain a snapshot of the electromagnetic field values of a specified volume of the model domain at a specified point in time during the simulation. By default snapshot files use the open source `Visualization ToolKit (VTK) <http://www.vtk.org>`_ format which can be viewed in many free readers, such as `Paraview <http://www.paraview.org>`_. Paraview is an open-source, multi-platform data analysis and visualization application. It is available for Linux, macOS, and Windows. You can optionally output snapshot files using the HDF5 format if desired.
+Snapshot files contain a snapshot of the electromagnetic field values of a specified volume of the model domain at a specified point in time during the simulation. By default, snapshot files use the open source `Visualization ToolKit (VTK) <http://www.vtk.org>`_ format which can be viewed in many free readers, such as `Paraview <http://www.paraview.org>`_. Paraview is an open-source, multi-platform data analysis and visualization application. It is available for Linux, macOS, and Windows. You can optionally output snapshot files using the HDF5 format if desired.
 
 .. tip::
     You can take advantage of our Python API to easily create a series of snapshots. For example, to create 30 snapshots starting at time 0.1ns until 3ns in intervals of 0.1ns, use the following code snippet in your input file. Replace ``x, y, z, dl, fn`` accordingly.
@@ -147,7 +147,7 @@ The ``#geometry_view:`` command produces either ImageData (.vti) for a per-cell
 
     Paraview toolbar showing ``gprMax`` macro button.
 
-#. **Open the file** either from the File menu or toolbar.
+#. **Open the file** either from the File menu or the toolbar.
 #. Click the **Apply** button in the Properties panel. You should see an outline of the volume of the geometry view.
 #. Install the ``gprMax.py`` Python script, that comes with the gprMax source code (in the ``toolboxes/Utilities/Paraview`` directory), as a macro in Paraview. This script makes it quick and easy to view the different materials in a geometry file. To add the script as a macro in Paraview choose the file from the Macros->Add new macro menu. It will then appear as a shortcut button in the toolbar as shown in :numref:`pv_toolbar`. You only need to do this once, the macro will be kept in Paraview for future use.
 #. Click the ``gprMax`` shortcut button. All the materials in the model should appear in the Pipeline Browser as Threshold items as shown in :numref:`pv_pipeline`.