[doc] Fix indentation issue.
--- a/doc/book/en/B0031-define-entities.en.txt Tue Apr 14 17:16:43 2009 -0700
+++ b/doc/book/en/B0031-define-entities.en.txt Tue Apr 14 17:17:34 2009 -0700
@@ -133,7 +133,7 @@
The method ``filterform_vocabulary(rtype, x, var, rqlst, args, cachekey)`` takes
the name of a relation and the target as parameters,
[XXX what does it mean ?]
- which indicates of the
+which indicates of the
entity on which we apply the method is subject or object of the relation. It
has to return: