add sphinx-autobuild

Change-Id: Idbb6976e34f029b6017a16fe5d8355c87b649315

Makefile

@@ -26,5 +26,10 @@ help:
 
 .PHONY: help Makefile
 
+# specific rule to use sphinx-autobuild
+watch: Makefile
+	@sphinx-autobuild -b html "$(SRC)" "$(OUT)"/html $(OPTS)
+
+# anything else
 %: Makefile
 	@$(CMD) -M $@ "$(SRC)" "$(OUT)" $(OPTS)

guides/how-to-contribute-to-this-documentation.rst

@@ -32,6 +32,12 @@ and the `MyST Markdown parser
 
    $ pip install --upgrade sphinx sphinx_rtd_theme myst_parser
 
+If you want to use the auto-build and auto-refresh feature, also install
+`sphinx-autobuild <https://github.com/executablebooks/sphinx-autobuild>`_.
+
+.. code-block:: bash
+
+   $ pip install --upgrade sphinx-autobuild
 
 Cloning the repository
 ======================
@@ -75,6 +81,16 @@ From the base of the repository, run:
 You should now be able to view the documentation in your web
 browser.  The homepage is at ``_build/html/index.html``.
 
+To automatically build the documentation and refresh your web browser whenever
+you save changes, run:
+
+.. code-block:: bash
+
+   $ make clean && make watch
+
+Keep this running in the background, then navigate to http://127.0.0.1:8000
+(*not* the local .html file).
+
 Saving your work
 ================