Fix a typo in documentation

[princemaple]

previously sent this PR #9693 but got closed due to CLA
I've signed CLA now.

Just English...

, event if

is obviously wrong...
changed to

, even if

[mary-poppins]

I'm sorry, but I wasn't able to verify your Contributor License Agreement (CLA) signature. CLA signature is required for any code contributions to AngularJS.

Please sign our CLA and ensure that the CLA signature email address and the email address in this PR's commits match.

If you signed the CLA as a corporation, please let us know the company's name.

Thanks a bunch!

PS: If you signed the CLA in the past then most likely the email addresses don't match. Please sign the CLA again or update the email address in the commit of this PR.
PS2: If you are a Googler, please sign the CLA as well to simplify the CLA verification process.

[princemaple]

I signed it just before sending this PR, as an individual. I also did attach my github username.

[rodyhaddad]

Pete already merged your PR last time
It's already in the codebase :) 303610c

[princemaple]

Ah cool. Thanks man.