Document the htmlview make target (python#857)

docquality.rst

@@ -120,16 +120,17 @@ you*. To build the devguide on a Unix-like system use::
 
    $ make html
 
-in the checkout directory. On Windows use:
+in the checkout directory.  On Windows use:
 
 .. code-block:: doscon
 
    > .\make html
 
-You will find the generated files in ``_build/html``. Note that ``make check``
-runs automatically when you submit a :doc:`pull request <pullrequest>`. You may
-wish to run ``make check`` and ``make linkcheck`` to make sure that it runs
-without errors.
+You will find the generated files in ``_build/html`` or, if you use
+``make htmlview``, the docs will be opened in a browser once the build
+completes.  Note that ``make check`` runs automatically when you submit
+a :doc:`pull request <pullrequest>`.  You may wish to run ``make check``
+and ``make linkcheck`` to make sure that it runs without errors.
 
 .. _separate repository:
 .. _devguide repo: https://github.com/python/devguide

documenting.rst

@@ -1544,7 +1544,9 @@ Using make / make.bat
    make venv
    make html
 
-or alternatively ``make -C Doc/ venv html``.
+or alternatively ``make -C Doc/ venv html``.  ``htmlview`` can be used
+instead of ``html`` to conveniently open the docs in a browser once the
+build completes.
 
 You can also use ``make help`` to see a list of targets supported by
 :command:`make`.  Note that ``make check`` is automatically run when