[1.2.X] Fixed #14627 -- Made Tutorial 3 more explicit regarding the...

[1.2.X] Fixed #14627 -- Made Tutorial 3 more explicit regarding the transformations the URLconf undergoes in the final two sections, and gave an example of concatenating two patterns() in the process. Thanks to filmer for the report.

Backport of [14472] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14473 bcc190cf-cafb-0310-a4f2-bffc1f526a37