docs($http): fixes grunt warning

[jesselpalmer]

When you run grunt package you get the following warning:

warn:    Dangling Links Found in "partials/api/ng/service/$http.html":
 - #overriding-the-default-transformations-per-request,
 - #overriding-the-default-transformations-per-request

This change fixes the links, so the warning will no longer appear.

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[jesselpalmer]

I've signed the CLA before. My email address in the CLA contains dots in it and the email address that I use for my git commits does not. I'll update the email address for my git commits so they match.

[caitp]

I think we should be able to just use ng.$http#... for this instead --- but it basically looks good, will merge it tonight if nobody else beats me to it

[googlebot]

We found a Contributor License Agreement for you (the sender of this pull request) and all commit authors, but as best as we can tell these commits were authored by someone else. If that's the case, please add them to this pull request and have them confirm that they're okay with these commits being contributed to Google. If we're mistaken and you did author these commits, just reply here to confirm.

[jesselpalmer]

I updated my email on my git commit and I guess the googlebot didn't like that too much. I made the changes as you requested though. Thanks @caitp!