Feature 2489 update docs

docs/Contributors_Guide/documentation.rst

@@ -218,7 +218,7 @@ for more information.
 
 **What to bold:**
 
-  * Variables (e.g. **MET_INSTALL_DIR, INPUT_BASE, METCALCPY_HOME**, etc.)
+  * Environment Variables (e.g. **MET_INSTALL_DIR, INPUT_BASE, METCALCPY_HOME**, etc.)
   * Filenames (**line_defaults.yaml, contour_defaults.yaml, defaults.conf**, etc.)
 
 Italics
@@ -395,6 +395,20 @@ resulting in the following displayed text:
 
 See `Overleaf's Guide - Matrices <https://www.overleaf.com/learn/latex/Matrices>`_ for more information.
 
+Literal Include
+---------------
+
+This feature is used often in the Release Guide, but there are other places it could be useful.
+Using a literal include ensures only having to update the documentation in one place.
+It is important to use a relative path (i.e. "../../") to get to the correct 
+directory of the file being referenced in the literal include.  This will keep the 
+file linking to the correct version and branch.  
+
+As an example, refer to the METplus User's Guide.  See this 
+`line <https://github.com/dtcenter/METplus/blob/46f705fc2c1b861e3aa6314d030eb9b4c382d0b3/docs/use_cases/met_tool_wrapper/PointStat/PointStat.py#L55>`_ 
+in the PointStat Wrapper Use Case documentation, which uses RST's :code:`.. literalinclude::` 
+and renders the text of the referenced file in this 
+`section <https://metplus.readthedocs.io/en/develop/generated/met_tool_wrapper/PointStat/PointStat.html#metplus-configuration>`_.
 
 Literal Blocks
 --------------
@@ -425,6 +439,54 @@ and
 `literal blocks <https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#literal-blocks>`_
 for more information.
 
+Substitution References
+-----------------------
+
+Substitution references are replacements in the text as defined in the :code:`rst_epilog` 
+in the **docs/conf.py** file.  For example, instead of hard coding the MET version in 
+the METplus documentation, a variable :code:`met_version` can be set to a value 
+(e.g. 12.0.0) in the **docs/conf.py** file in the following way:
+
+.. code-block:: ini
+
+  met_version = 12.0.0
+
+Then, this variable is used in the :code:`rst_epilog` to set up the substitution, 
+along with other variables.  For example, in the **docs/conf.py** 
+file the following is defined:
+
+.. code-block:: ini
+
+  rst_epilog = f"""
+  .. |copyright|    replace:: {copyright}
+  .. |author_list|  replace:: {author_list}
+  .. |release_date| replace:: {release_date}
+  .. |release_year| replace:: {release_year}
+  .. |release_info| replace:: {release_info}
+  .. |python_version| replace:: {python_version}
+  .. |met_version| replace:: {met_version}
+  """
+
+The value 12.0.0 would then be replaced in the documentation wherever 
+:code:`|met_version|` is used in .rst files.  For example:
+
+.. code-block:: ini
+
+  MET version |met_version| or above 
+
+There are some 
+`reserved substitution variables <https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html#substitutions>`_ 
+in Sphinx.  These variables are 
+:code:`|release|`, :code:`|version|`, :code:`|today|`, and 
+:code:`|translation progress|`. Reserved substitution variables do not 
+need to be added to :code:`rst_epilog`, but other variables do.
+
+See 
+`Substitutions <https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html#substitutions>`_ 
+and 
+`rst_epilog <https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-rst_epilog>`_ 
+for more information.
+
 Line Blocks
 -----------