Add a tip about re-using $ entities in example version strings.

svn path=/head/; revision=47702

en_US.ISO8859-1/books/fdp-primer/po-translations/chapter.xml

@@ -676,6 +676,38 @@ DOC_PREFIX?=    ${.CURDIR}/../../..
       </itemizedlist>
     </sect2>
 
+    <sect2 xml:id="po-translations-literal-dollar">
+      <title><literal>&dollar;FreeBSD&dollar;</literal>
+	Strings</title>
+
+      <para>The &dollar;FreeBSD&dollar; version strings used in
+	files require special handling.  In examples like
+	<xref linkend="po-translations-creating-example"/>, these
+	strings are not meant to be expanded.  The English documents
+	use <literal>&amp;dollar;</literal> entities to avoid
+	including actual literal dollar signs in the file:</para>
+
+      <programlisting>&amp;dollar;FreeBSD&amp;dollar;</programlisting>
+
+      <para>The <literal>&amp;dollar;</literal> entities are not seen
+	as dollar signs by the version control system and so the
+	string is not expanded into a version string.</para>
+
+      <para>When a <acronym>PO</acronym> file is created, the
+	<literal>&amp;dollar;</literal> entities used in examples are
+	replaced with actual dollar signs.  The resulting literal
+	<literal>&dollar;FreeBSD&dollar;</literal> string will be
+	wrongly expanded by the version control system when the file
+	is committed.</para>
+
+      <para>The same technique as used in the English documents can be
+	used in the translation.  The <literal>&amp;dollar;</literal>
+	is used to replace the dollar sign in the translation entered
+	into the <acronym>PO</acronym> editor:</para>
+
+      <programlisting>&amp;dollar;FreeBSD&amp;dollar;</programlisting>
+    </sect2>
+
     <!--
     <sect2 xml:id="po-translations-tips-makefile">
       <title>Modifying the <filename>Makefile</filename></title>