- Use of double-quotation marks instead of single ones

- Remove useless quotation marks

Nice reference:
http://webster.commnet.edu/grammar/marks/quotation.htm

en_US.ISO8859-1/books/fdp-primer/tools/chapter.sgml

@@ -119,7 +119,7 @@
 	    (<filename role="package">www/tidy</filename>)</term>
 	  
 	  <listitem>
-	    <para>An HTML 'pretty printer', used to reformat some of the
+	    <para>An HTML <quote>pretty printer</quote>, used to reformat some of the
 	      automatically generated HTML so that it is easier to
 	      follow.</para>
 	  </listitem>
@@ -180,7 +180,7 @@
 	  <listitem>
 	    <para>19 of the ISO 8879:1986 character entity sets used by many
 	      DTDs.  Includes named mathematical symbols, additional
-	      characters in the 'Latin' character set (accents, diacriticals,
+	      characters in the Latin character set (accents, diacriticals,
 	      and so on), and Greek symbols.</para>
 	  </listitem>
 	</varlistentry>