Fix examples of $location.html5mode in the documentation

While learning about the $location service, I read the docs on:

http://docs.angularjs.org/guide/dev_guide.services.$location

In one of the examples, it was written in the config setter was: 

$locationProvider.html5mode = true;

So I tried it, and debugged it and couldn't get it to work.
Only after continuing to read on, I saw another version of the same config flag:

$.locationProvider.html5Mode( true )

and that one worked.

So I changed the examples to the working one.
Shai