Mention the --tool option in the manual page. Fixes #249970.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11979 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/docs/xml/manual-core.xml b/docs/xml/manual-core.xml
index de0d333..1e03d66 100644
--- a/docs/xml/manual-core.xml
+++ b/docs/xml/manual-core.xml
@@ -564,9 +564,9 @@
 <sect2 id="manual-core.toolopts" xreflabel="Tool-selection Option">
 <title>Tool-selection Option</title>
 
-<para>The single most important option.</para>
+<para id="tool.opts.para">The single most important option.</para>
 
-<variablelist>
+<variablelist id="tool.opts.list">
 
   <varlistentry id="tool_name" xreflabel="--tool">
     <term>