documentation_hacking.xml: Update reference to epubcheck.

	* doc/xml/manual/documentation_hacking.xml: Update reference
	to epubcheck.

From-SVN: r266970

libstdc++-v3/ChangeLog

@@ -1,3 +1,8 @@
+2018-12-10  Gerald Pfeifer  <[email protected]>
+
+	* doc/xml/manual/documentation_hacking.xml: Update reference
+	to epubcheck.
+
 2018-12-10  Jonathan Wakely  <[email protected]>
 
 	* testsuite/experimental/filesystem/path/query/is_absolute.cc: Fix

libstdc++-v3/doc/xml/manual/documentation_hacking.xml

@@ -777,7 +777,7 @@
       </para>
 
       <para>
-	For epub output, the <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://sourceforge.net/projects/docbook/files/epub3/">stylesheets</link> for EPUB3 are required. These stylesheets are still in development. To validate the created file, <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://github.com/IDPF/epubcheck">epubcheck</link> is necessary.
+	For epub output, the <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://sourceforge.net/projects/docbook/files/epub3/">stylesheets</link> for EPUB3 are required. These stylesheets are still in development. To validate the created file, <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://github.com/w3c/epubcheck">epubcheck</link> is necessary.
       </para>
     </section>