Updated $interval documentation

[sharppanda]

callback function return parameter with iteration count

[mary-poppins]

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[caitp]

This has two problems with it.

1. it makes jscs/jshint yell at us

2. it doesn't actually output any new information in the rendered docs.

Better solution, make a note about the callback function signature in the description of the parameter.

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[rodyhaddad]

You updated the docs in the ngMock version of $interval.
The same doc mistake exists in the main $interval implementation.
I believe that's what Cait means with 2)

---

What's surprising, is that this behavior isn't tested at all, so I wonder if we want it or not.
cc @juliemr

[caitp]

Actually, I didn't look at the mock documentation, so maybe I'm wrong. But it looks like function parameters don't get serialized in any way in the function parameter docs

[caitp]

Okay, it is getting rendered in this case, although it doesn't actually look very good. So that's better than nothing. Ignore criticism 2 and fix the jscs/jshint issues, we can merge this

[sharppanda]

This is my first try of updating the documentation.
How can I see the results from jscs/jshint?
Where can I see the final documentation with my change?

[gkalpak]

Closing as this is not in a merge-able sate. Feel free to open a new PR.

_{BTW, you can see the failures either here or by running the tests locally on your machine (e.g. grunt ci-checks). For more info see there.}