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>
1 file changed