Optional lessons lesson plans

The links for the optional lessons incsp unit 1 are broken.

the lesson plans for the optional lessons are currently linking to addresses like:

https://curriculum.code.org/csp-19/unit1/11/optional/17/
https://curriculum.code.org/csp-19/unit1/11/optional/18/
https://curriculum.code.org/csp-19/unit1/11/optional/19/

but should link to:

https://curriculum.code.org/csp-19/unit1/11/optional/1/
https://curriculum.code.org/csp-19/unit1/11/optional/2/
https://curriculum.code.org/csp-19/unit1/11/optional/3/

Hi @dahlem_brian - thanks for bringing this to our attention. We will work on fixing the links!

Please also feel free to submit bugs like this to support@code.org to increase visibility.

Cheers!
~ Hannah

All fixed! Thanks again for letting us know.