Several small documentation updates (#2558)

docs/source/devguide/docbuild.rst

@@ -5,21 +5,14 @@ Building Sphinx Documentation
 =============================
 
 In order to build the documentation in the ``docs`` directory, you will need to
-have the `Sphinx <https://www.sphinx-doc.org/en/master/>`_ third-party Python
-package. The easiest way to install Sphinx is via pip:
+have the several third-party Python packages installed, including `Sphinx
+<https://www.sphinx-doc.org/en/master/>`_. To install the necessary
+prerequisites, provide the optional "docs" dependencies when installing OpenMC's
+Python API. That is, from the root directory of the OpenMC repository:
 
 .. code-block:: sh
 
-    pip install sphinx
-
-Additionally, you will need several Sphinx extensions that can be installed
-directly with pip:
-
-.. code-block:: sh
-
-    pip install sphinx-numfig
-    pip install sphinxcontrib-katex
-    pip install sphinxcontrib-svg2pdfconverter
+    python -m pip install .[docs]
 
 -----------------------------------
 Building Documentation as a Webpage

docs/source/devguide/tests.rst

@@ -23,11 +23,7 @@ Prerequisites
   OpenMC in development/editable mode. With setuptools, this is accomplished by
   running::
 
-      python setup.py develop
-
-  or using pip (recommended)::
-
-      pip install -e .[test]
+      python -m pip install -e .[test]
 
 - The test suite requires a specific set of cross section data in order for
   tests to pass. A download URL for the data that OpenMC expects can be found
@@ -83,13 +79,13 @@ does not exist run::
 
     touch test_<name-of-header-file>.cpp
 
-The file must be added to the CMake build system in 
-``tests/cpp_unit_tests/CMakeLists.txt``. ``test_<name-of-header-file>`` should 
-be added to ``TEST_NAMES``. 
+The file must be added to the CMake build system in
+``tests/cpp_unit_tests/CMakeLists.txt``. ``test_<name-of-header-file>`` should
+be added to ``TEST_NAMES``.
 
-To add a test case to ``test_<name-of-header-file>.cpp`` ensure 
-``catch2/catch_test_macros.hpp`` is included. A unit test can then be added 
-using the ``TEST_CASE`` macro and the ``REQUIRE`` assertion from Catch2. 
+To add a test case to ``test_<name-of-header-file>.cpp`` ensure
+``catch2/catch_test_macros.hpp`` is included. A unit test can then be added
+using the ``TEST_CASE`` macro and the ``REQUIRE`` assertion from Catch2.
 
 Adding Tests to the Regression Suite
 ------------------------------------

docs/source/devguide/workflow.rst

@@ -116,7 +116,7 @@ pip_. From the root directory of the OpenMC repository, run:
 
 .. code-block:: sh
 
-    pip install -e .[test]
+    python -m pip install -e .[test]
 
 This installs the OpenMC Python package in `"editable" mode
 <https://pip.pypa.io/en/stable/cli/pip_install/#editable-installs>`_ so that 1)