append new Fields to field_components

[grayeul]

What does it do?

This fixes a typo in the tutorial, in one of the python snippets for the tic-tac-toe app.

Why is it needed?

The step-wise tutorial doesn't work without it.

How to test it?

This is a minor change that fixes an obvious typographical error.

Related issue(s)/PR(s)

I didn't create a separate issue for this, as it was a simple fix/change.

[Aran-Fey]

Thanks for the fix!