Document generating ctags tests using the pretty-printing script

HACKING

@@ -699,9 +699,13 @@ It can be either long or short, depending on what it tests.
 
 The expected output should be in the file ``tests/ctags/mytest.ext.tags``
 (which is the same name as the source, but with ``.tags`` appended), and
-should be in the format generated by ``geany -g``. This file contains
-the tag information expected to be generated from the corresponding
-source file.
+should be in the format generated by::
+
+    $ geany -g tmp.ext.tags tests/ctags/mytest.ext
+    $ scripts/print-tags.py < tmp.ext.tags > tests/ctags/mytest.ext.tags
+
+This file contains the tag information expected to be generated from
+the corresponding source file together with its human-readable form.
 
 When you have these two files, you have to list your new test along the
 other ones in the ``test_source`` variable in ``tests/ctags/Makefile.am``.