docs-rst: doc-guide: Minor grammar fixes

While using this guide to learn the new documentation method, I saw
a few phrases that I felt could be improved. These small changes
improve the grammar and choice of words to further enhance the
installation instructions.

Signed-off-by: Joel Nider <joeln@il.ibm.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/doc-guide/sphinx.rst b/Documentation/doc-guide/sphinx.rst
index 02605ee..c039224 100644
--- a/Documentation/doc-guide/sphinx.rst
+++ b/Documentation/doc-guide/sphinx.rst
@@ -27,8 +27,8 @@
 ==============
 
 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.
+built with ``Sphinx`` version 1.3 or higher. If you desire to build
+PDF output, it is recommended to use version 1.4.6 or higher.
 
 There's a script that checks for the Sphinx requirements. Please see
 :ref:`sphinx-pre-install` for further details.
@@ -37,15 +37,15 @@
 and it is not uncommon that upgrading it or some other Python packages
 on your machine would cause the documentation build to break.
 
-A way to get rid of that is to use a different version than the one shipped
-on your distributions. In order to do that, it is recommended to install
+A way to avoid that is to use a different version than the one shipped
+with your distributions. In order to do so, it is recommended to install
 Sphinx inside a virtual environment, using ``virtualenv-3``
 or ``virtualenv``, depending on how your distribution packaged Python 3.
 
 .. note::
 
    #) Sphinx versions below 1.5 don't work properly with Python's
-      docutils version 0.13.1 or upper. So, if you're willing to use
+      docutils version 0.13.1 or higher. So, if you're willing to use
       those versions, you should run ``pip install 'docutils==0.12'``.
 
    #) It is recommended to use the RTD theme for html output. Depending
@@ -82,7 +82,7 @@
 PDF and LaTeX builds
 --------------------
 
-Such builds are currently supported only with Sphinx versions 1.4 and upper.
+Such builds are currently supported only with Sphinx versions 1.4 and higher.
 
 For PDF and LaTeX output, you'll also need ``XeLaTeX`` version 3.14159265.