Fix typo in Quiz ch04-01-ownership-sec2-moves.toml

[MisterDerpie]

Where

Chapter 04.01. - What is Ownership? - Quiz at the bottom of the page, Question 3

What

Fix typo.

... or select "None of the above" is none of these snippets would cause undefined behavior

Why

• Is: is
• Should be: if

[willcrichton]

Thanks!