docs fix - orm internals, should be 'attrs' not 'attr'

[Former user]

(original reporter: jonathan) this appears in the .8 and latest docs

http://docs.sqlalchemy.org/en/latest/orm/internals.html http://docs.sqlalchemy.org/en/rel_0_8/orm/internals.html

   insp = inspect(some_mapped_object)
-  attr_state = insp.attr.some_attribute
+  attr_state = insp.attrs.some_attribute

[Mike Bayer]

b9bd6ffd43a138f0b8964ca master

9fa0088d438c0abed6027 0.8

[Mike Bayer]

Removing milestone: 0.8.xx (automated comment)