Add a command snippet to build only modified documentation (#10571)

Add a command snippet to build only modified documentation

Clarified that the FILELIST feature isn't available on Windows, hint about WSL.
Added examples for diff from HEAD and master.

Author: Maarrk

contributing/documentation/building_the_manual.rst

@@ -162,8 +162,33 @@ RAM for Sphinx alone.
 Specifying a list of files
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+.. warning::
+
+    This section will not work on Windows, since the repository is using
+    a simplified ``make.bat`` script instead of the real GNU Make program.
+    If you would like to get a Linux terminal on your system, consider using
+    `Windows Subsystem for Linux (WSL) <https://learn.microsoft.com/en-us/windows/wsl/>`__.
+
 You can specify a list of files to build, which can greatly speed up compilation:
 
 .. code:: sh
 
     make html FILELIST='classes/class_node.rst classes/class_resource.rst'
+
+The list of files can also be provided by the ``git`` command.
+This way you can automatically get the names of all files that have changed since
+the last commit (``sed`` is used to put them on the same line).
+
+.. code:: sh
+
+    make html FILELIST="$(git diff HEAD --name-only | sed -z 's/\n/ /g')"
+
+You can replace ``HEAD`` with ``master`` to return all files changed from the
+``master`` branch:
+
+.. code:: sh
+
+    make html FILELIST="$(git diff master --name-only | sed -z 's/\n/ /g')"
+
+If any images were modified, the output will contain some warnings about them,
+but the build will proceed correctly.