Revised documentation on localization, a=chris

diff --git a/en-US/pages/documentation.thtml b/en-US/pages/documentation.thtml
index d43a69a..ea476d5 100755
--- a/en-US/pages/documentation.thtml
+++ b/en-US/pages/documentation.thtml
@@ -2196,6 +2196,13 @@ OdpRdfArchiveBundle
     2 = page count dump wikipedia data,
     3 = page count dump wiktionary data.
     </pre>
+    <p>The filter file produced by the above command can be found in:</p>
+    <pre>
+    WORK_DIRECTORY/locale/which-locale-tag-you-used/resources/n_word_grams.ftr
+    </pre>
+    <p>Rather than pick a specific n such as 2 or 3 you can also use the
+    keyword <tt>all</tt> to get max_to_extract many n-grams of up to
+    arbitrary length.</p>

     <h3>Obtaining data sets for token_tool.php</h3>
     <p>