docs-rst: move Sphinx install instructions to sphinx.rst

The toolchain used by Sphinx is somewhat complex, and installing
it should be part of the doc-guide.

Move it out of changes.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/doc-guide/sphinx.rst

@@ -19,6 +19,23 @@ Finally, there are thousands of plain text documentation files scattered around
 ``Documentation``. Some of these will likely be converted to reStructuredText
 over time, but the bulk of them will remain in plain text.
 
+.. _sphinx_install:
+
+Sphinx Install
+==============
+
+The ReST markups currently used by the Documentation/ files are meant to be
+built with ``Sphinx`` version 1.3 or upper. If you're desiring to build
+PDF outputs, it is recommended to use version 1.4.6 or upper.
+
+.. note::
+
+  Please notice that, for PDF and LaTeX output, you'll also need ``XeLaTeX``
+  version 3.14159265. Depending on the distribution, you may also need to
+  install a series of ``texlive`` packages that provide the minimal set of
+  functionalities required for ``XeLaTex`` to work. For PDF output you'll also
+  need ``convert(1)`` from ImageMagick (https://www.imagemagick.org).
+
 Sphinx Build
 ============
 

Documentation/process/changes.rst

@@ -309,18 +309,8 @@ Kernel documentation
 Sphinx
 ------
 
-The ReST markups currently used by the Documentation/ files are meant to be
-built with ``Sphinx`` version 1.3 or upper. If you're desiring to build
-PDF outputs, it is recommended to use version 1.4.6 or upper.
-
-.. note::
-
-  Please notice that, for PDF and LaTeX output, you'll also need ``XeLaTeX``
-  version 3.14159265. Depending on the distribution, you may also need to
-  install a series of ``texlive`` packages that provide the minimal set of
-  functionalities required for ``XeLaTex`` to work. For PDF output you'll also
-  need ``convert(1)`` from ImageMagick (https://www.imagemagick.org).
-
+Please see :ref:`sphinx_install` in ``Documentation/doc-guide/sphinx.rst``
+for details about Sphinx requirements.
 
 Getting updated software
 ========================