docs(error/dupes): Little fix in explanation text.

[Juanmcuello]

No description provided.

[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.

[caitp]

Lgtm

[caitp]

@Juanmcuello can you sign the CLA please? Apparently we need to ask for CLAs even for things like this now.

I will land this anyways, but please do be sure to sign, @mary-poppins posted a link in the message above. If you have signed already, please let me know, thanks.

[Juanmcuello]

@caitp , I already signed the CLA. Cheers.