Fixed a typo in forms.ngdoc

[mikeg0184]

No description provided.

[mary-poppins]

Thanks for the PR! Please check the items below to help us merge this faster. See the contributing docs for more information.

• Uses the issue template (#6556)

If you need to make changes to your pull request, you can update the commit with git commit --amend.
Then, update the pull request with git push -f.

Thanks again for your help!

[pkozlowski-opensource]

Thank you @mgerstenblatt !