Bug 12244 - Update Admin Help for 3.16

Bug 12244 - Update Admin Help for 3.16

This patch updates 3 help files.

To test:

* Visit Administration > Patron Categories
* Click help
* Confirm it's there and right
* Visit Administration > Currencies
* Click help
* Confirm it's there and right
* Visit Administration > Circ Rules
* Click help
* Confirm it's there and right

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Help ok. One comment: on circ rules, I think that "you're" can
be correct, but I prefer "you are"

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>